IPA: allow initgroups by SID for AD users
If a user from a trusted AD domain is search with the help of an
override name the SID from the override anchor is used to search the
user in AD. Currently the initgroups request only allows searches by
name. With this patch a SID can be used as well.
Resolves https://fedorahosted.org/sssd/ticket/2632
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
(cherry picked from commit f70a1adbfc30b9acc302027439fb8157e0c6ea2a)