Corrected .gitignore patterns for plugins
Corrected .gitignore patterns for plugins

New patterns whitelist existing plugins and ignores
new ones added by the user.

Change-Id: I942869f2e91e678189defab0bfb74f18c60c08ac
Signed-off-by: Sorin Sbarnea <8938dff14221394d430a023580a32caf3bfb26a9@redhat.com>

redhat-openstack/infrared,redhat-openstack/infrared,redhat-openstack/infrared