##### 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

description: Master status information.
  returned: if master
  type: dict
  sample:
  - { "Binlog_Do_DB": "", "Binlog_Ignore_DB": "mysql", "File": "mysql-bin.000001", "Position": 769 }
slave_status:
  description: Slave status information.
  returned: if standby
  type: dict
  sample:
  - { "192.168.1.101": { "3306": { "replication_user": { "Connect_Retry": 60, "Exec_Master_Log_Pos": 769,  "Last_Errno": 0 } } } }
slave_hosts:
  description: Slave status information.
  returned: if master
  type: dict
  sample:
  - { "2": { "Host": "", "Master_id": 1, "Port": 3306 } }
'''
from decimal import Decimal
from ansible.module_utils.basic import AnsibleModule
from ansible.module_utils.mysql import (
    mysql_connect,
    mysql_common_argument_spec,
    mysql_driver,
    mysql_driver_fail_msg,
)
from ansible.module_utils.six import iteritems
from ansible.module_utils._text import to_native
#
class MySQL_Info(object):