When a group is renamed then the group has been invalidated for sure.
In that case get the group information using the new name.

Add a regression test about this bug

PR:		193704
Reported by:	az


git-svn-id: svn+ssh://svn.freebsd.org/base/head@273772 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f