s/OpenStack LLC/OpenStack Foundation/ in Copyright.

Update Copyright statements that previously said 'OpenStack LLC' to now
say 'OpenStack Foundation'.  Note that the files under openstack/common/
were not updated, as those changes should be brought in by syncing with
oslo-incubator.

Change-Id: I22db9858e899cff72053a4b48100fcc039f5d9dd
Merge "s/OpenStack LLC/OpenStack Foundation/ in Copyright."