##### SUMMARY
See https://app.shippable.com/github/ansible-collections/community.general/runs/6193/46/console for an example, I've already seen this multiple times today (also on AZP).

`ansible-galaxy -vvv collection install ansible.posix` was run three times in a row, and ~~always~~ two times out of three failed with `This collection only contains pre-releases.` (the first fail was a read timeout):

```
+ ansible-galaxy -vvv collection install ansible.posix
01:54 [DEPRECATION WARNING]: Ansible will require Python 3.8 or newer on the 
01:54 controller starting with Ansible 2.12. Current version: 2.7.15+ (default, Feb  
01:54 9 2019, 11:33:22) [GCC 5.4.0 20160609]. This feature will be removed from 
01:54 ansible-core in version 2.12. Deprecation warnings can be disabled by setting 
01:54 deprecation_warnings=False in ansible.cfg.
01:54 /root/venv/lib/python2.7/site-packages/ansible/parsing/vault/__init__.py:44: CryptographyDeprecationWarning: Python 2 is no longer supported by the Python core team. Support for it is now deprecated in cryptography, and will be removed in the next release.
01:54   from cryptography.exceptions import InvalidSignature
01:55 [WARNING]: You are running the development version of Ansible. You should only
01:55 run Ansible from "devel" if you are modifying the Ansible engine, or trying out
01:55 features under development. This is a rapidly changing source of code and can
01:55 become unstable at any point.
01:55 [DEPRECATION WARNING]: Setting verbosity before the arg sub command is 
01:55 deprecated, set the verbosity after the sub command. This feature will be 
01:55 removed from ansible-core in version 2.13. Deprecation warnings can be disabled
01:55  by setting deprecation_warnings=False in ansible.cfg.
01:55 ansible-galaxy 2.11.0.dev0
01:55   config file = None
01:55   configured module search path = [u'/root/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
01:55   ansible python module location = /root/venv/lib/python2.7/site-packages/ansible
01:55   ansible collection location = /root/.ansible
01:55   executable location = /root/venv/bin/ansible-galaxy
01:55   python version = 2.7.15+ (default, Feb  9 2019, 11:33:22) [GCC 5.4.0 20160609]
01:55   jinja version = 2.11.2
01:55   libyaml = True
01:55 No config file found; using defaults
01:55 Starting galaxy collection install process
01:55 Found installed collection ansible.netcommon:1.4.1 at '/root/.ansible/ansible_collections/ansible/netcommon'
01:55 Found installed collection community.kubernetes:1.1.1 at '/root/.ansible/ansible_collections/community/kubernetes'
01:55 Found installed collection community.internal_test_tools:0.2.1 at '/root/.ansible/ansible_collections/community/internal_test_tools'
01:55 Skipping '/root/.ansible/ansible_collections/community/general/.git' for collection build
01:55 Skipping '/root/.ansible/ansible_collections/community/general/galaxy.yml' for collection build
01:55 Found installed collection community.general:2.0.0 at '/root/.ansible/ansible_collections/community/general'
01:55 Found installed collection google.cloud:1.0.1 at '/root/.ansible/ansible_collections/google/cloud'
01:55 Process install dependency map
01:55 Processing requirement collection 'ansible.posix'
01:55 Opened /root/.ansible/galaxy_token
01:56 Collection 'ansible.posix' obtained from server default https://galaxy.ansible.com/api/
01:56 ERROR! Cannot meet requirement * for dependency ansible.posix from source 'https://galaxy.ansible.com/api/'. Available versions before last requirement added: 
01:56 Requirements from:
01:56 	base - 'ansible.posix:*'
01:56 This collection only contains pre-releases. Utilize `--pre` to install pre-releases, or explicitly provide the pre-release version.
```

It could be that for some reason, only the first page of the results is queried (https://galaxy.ansible.com/api/v2/collections/ansible/posix/versions/), which contains only pre-releases. I guess this is probably a problem on Galaxy's side, but in case it is not, I'm creating this issue in ansible/ansible.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
ansible-galaxy collection

##### ANSIBLE VERSION
```paste below
devel
```

""" This class is meant to be used as a API client for an Ansible Galaxy server """
    def __init__(
            self, galaxy, name, url,
            username=None, password=None, token=None, validate_certs=True,
            available_api_versions=None,
            clear_response_cache=False, no_cache=True,
            priority=float('inf'),
    ):
        self.galaxy = galaxy
        self.name = name
        self.username = username
        self.password = password
        self.token = token
        self.api_server = url
        self.validate_certs = validate_certs
        self._available_api_versions = available_api_versions or {}
        self._priority = priority
        b_cache_dir = to_bytes(C.config.get_config_value('GALAXY_CACHE_DIR'), errors='surrogate_or_strict')
        makedirs_safe(b_cache_dir, mode=0o700)
        self._b_cache_path = os.path.join(b_cache_dir, b'api.json')
        if clear_response_cache:
            with _CACHE_LOCK:
                if os.path.exists(self._b_cache_path):
                    display.vvvv("Clearing cache file (%s)" % to_text(self._b_cache_path))
                    os.remove(self._b_cache_path)
        self._cache = None
        if not no_cache:
            self._cache = _load_cache(self._b_cache_path)
        display.debug('Validate TLS certificates for %s: %s' % (self.api_server, self.validate_certs))
    def __str__(self):