aaa: Fix search to search properly for users by groups

Instead of ilike 'group%' which is problematic in case the
user is member of multiple groups , the pattern matching
operator is used with a proper expression to replace the %
wildcard.

Topic: AAA
Change-Id: I14e795926cb57de15b628587d5c3df427518720a
Signed-off-by: Yair Zaslavsky <yzaslavs@redhat.com>