<!--- Verify first that your issue is not already reported on GitHub -->
<!--- Also test if the latest release and devel branch are affected too -->
<!--- Complete *all* sections as described, this form is processed automatically -->

##### SUMMARY
docker_container is not idempotent when specifying an ip address

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
docker_container

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
ansible 2.8.5
  config file = /home/pkueck/projects/cix.de/cix-ansible/ansible.cfg
  configured module search path = ['/home/xxx/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python3.7/site-packages/ansible
  executable location = /usr/bin/ansible
  python version = 3.7.4 (default, Jul  9 2019, 16:32:37) [GCC 9.1.1 20190503 (Red Hat 9.1.1-1)]
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below
n/a
```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
Fedora 30, CentOS 7

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->

<!--- Paste example playbooks or commands between quotes below -->
```yaml
---
- hosts: myhost
  gather_facts: no
  tasks:
    - docker_network:
        name: "foonet"
        ipam_config:
          - subnet: 172.16.44.0/24
    - docker_container:
        name: "foo"
        state: present
        image: centos
        networks:
          - name: foonet
            ipv4_address: "172.16.44.11"
        networks_cli_compatible: yes
      loop: [1,2]
```

<!--- HINT: You can paste gist.github.com links for larger files -->

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
container created on first loop cycle, not touched on second one

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->

<!--- Paste verbatim command output between quotes -->
```paste below
PLAY [myhost] ***************

TASK [docker_network] *******
ok: [myhost]

TASK [docker_container] *****
--- before
+++ after
@@ -1,9 +1,10 @@
 {
-    "exists": false,
+    "exists": true,
     "network.foonet": {
         "aliases": null,
-        "ipv4_address": "",
-        "ipv6_address": "",
+        "id": "27e539c3b9af0160f02a0532ad081d1bd1ef3dd93e652095ec96d6dfd95bf2fb",
+        "ipv4_address": "172.16.44.11",
+        "ipv6_address": null,
         "links": null,
         "name": "foonet"
     }

changed: [myhost] => (item=1)
--- before
+++ after
@@ -1,10 +1,9 @@
 {
     "network.foonet": {
-        "aliases": [
-            "44cfded131d7"
-        ],
-        "ipv4_address": "",
-        "ipv6_address": "",
+        "aliases": null,
+        "id": "27e539c3b9af0160f02a0532ad081d1bd1ef3dd93e652095ec96d6dfd95bf2fb",
+        "ipv4_address": "172.16.44.11",
+        "ipv6_address": null,
         "links": null,
         "name": "foonet"
     }

changed: [myhost] => (item=2)
```

description:
      - Dictionary of key,value pairs.
    type: dict
    version_added: 2.4
  user:
    description:
      - Sets the username or UID used and optionally the groupname or GID for the specified command.
      - "Can be [ user | user:group | uid | uid:gid | user:gid | uid:group ]"
    type: str
  uts:
    description:
      - Set the UTS namespace mode for the container.
    type: str
  volumes:
    description:
      - List of volumes to mount within the container.
      - "Use docker CLI-style syntax: C(/host:/container[:mode])"
      - "Mount modes can be a comma-separated list of various modes such as C(ro), C(rw), C(consistent),
        C(delegated), C(cached), C(rprivate), C(private), C(rshared), C(shared), C(rslave), C(slave), and
        C(nocopy). Note that the docker daemon might not support all modes and combinations of such modes."
      - SELinux hosts can additionally use C(z) or C(Z) to use a shared or
        private label for the volume.
      - "Note that Ansible 2.7 and earlier only supported one mode, which had to be one of C(ro), C(rw),
        C(z), and C(Z)."
    type: list
  volume_driver:
    description:
      - The container volume driver.
    type: str
  volumes_from: