##### SUMMARY
mysql_user module with check_implicit_admin=yes try to connect to database without password. But when login failed doesn't fallback to login_user and login_password credentials.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
mysql_user

##### ANSIBLE VERSION
```
2.9.0
```

##### OS / ENVIRONMENT
Ubuntu 18.04

##### STEPS TO REPRODUCE
```yaml
- name: Update root password for all root accounts
  mysql_user: name=root password={{ mysql_root_password }} login_user=root login_password={{ mysql_root_password }} host={{ item }} check_implicit_admin=yes
  with_items:
    - "{{ current_hostname.stdout | lower }}"
    - 127.0.0.1
    - ::1
    - localhost
```

First run is ok, but on second run Ansible failed when try to connect as root without password and no fallback to login credentials.

##### EXPECTED RESULTS
First run -> root / no password
Other runs -> root / mysql_root_password

##### ACTUAL RESULTS
Provision failed at other as first run

from __future__ import absolute_import, division, print_function
__metaclass__ = type
ANSIBLE_METADATA = {
    'metadata_version': '1.1',
    'status': ['preview'],
    'supported_by': 'community'
}
DOCUMENTATION = r'''
---
module: mysql_info
short_description: Gather information about MySQL servers
description:
- Gathers information about MySQL servers.
version_added: '2.9'
options:
  filter:
    description:
    - Limit the collected information by comma separated string or YAML list.
    - Allowable values are C(version), C(databases), C(settings), C(global_status),
      C(users), C(engines), C(master_status), C(slave_status), C(slave_hosts).
    - By default, collects all subsets.
    - You can use '!' before value (for example, C(!settings)) to exclude it from the information.
    - If you pass including and excluding values to the filter, for example, I(filter=!settings,version),
      the excluding values, C(!settings) in this case, will be ignored.
    type: list