Add .idea pattern to .gitignore
Add .idea pattern to .gitignore

The .idea directoy is used by pycharm and should not be included
in the change list. The change extends the .gitignore file to
avoid .idea directory to be shown in the change list.

Change-Id: I439619d053439fa66ebf74a054d99b1378fb1733

noironetworks/heat,openstack/heat,noironetworks/heat,openstack/heat