aaa: Changing search logic at internal authz

If the user that is searched is not substring
(asteriks are taken into consideration) of the admin
user name, the internal authz will not return a user

Topic: AAA
Change-Id: I2ae66d23862ad5d4da2f2e2e6a903119e859fd39
Bug-Url: https:/bugzilla.redhat.com/1100321
Signed-off-by: Yair Zaslavsky <yzaslavs@redhat.com>