Adding test Coverage for mysql_variable module

Use mysql_variable to query, set and update variables.
Assert using user and password to query, set and update  variables.
Assert using single quotes, double quotes and no quotes  when using variables
Add support for environment variables in GCE module.
"allow_no_value=True" for ini_file module so /etc/my.cnf can be read without a problem
Update our search code for the doc site.
Update version.
Merge pull request #8397 from lukesneeringer/gce-envvars

Add support for environment variables in GCE module.
Merge pull request #8398 from wrosario/integration_mysql_variables

Adding test Coverage for mysql_variable module
Merge pull request #8400 from nicocesar/devel

"allow_no_value=True" for ini_file module
Merge pull request #8405 from wenottingham/patch-2

Update version.
Add version_added attribute for regexp parameter.
adding initial tests