NSS: Initgr memory cache should work with fq names
We need to stored two versions of name to the initgroups memory cache.
Otherwise it could be stored many times if sssd is configured with
case_sensitive = false. It would be impossible to invalidate all
version of names after user login. As a result of this wrong user
groups could be returned from initgroups memory cache.
Therefore we store raw name provided by glibc function
and internal sanitized fully qualified name,
which is unique for particular user.
This patch also increase average space for initgroups
because there are also stored two quite long names in case of
Reviewed-by: Michal Židek <firstname.lastname@example.org>