Add etc/*.conf files to .gitignore
Add etc/*.conf files to .gitignore

This commit makes etc/*.conf files be ignored from git repo. We don't
need to track user configuration files not only tempest.conf but also
the others such as custom-tempest.conf.

Change-Id: I46b3828426a37291205812bf377e7eeece9b7e0b

cisco-openstack/tempest,masayukig/tempest,masayukig/tempest,openstack/tempest,cisco-openstack/tempest,openstack/tempest