staging: lustre: fix quotactl permission denied (LU-4530)

The changes introduced in commit 4b1a25f0 ("fix build when
CONFIG_UIDGID_STRICT_TYPE_CHECKS is on") got the UID check the wrong way
around, leading to "Permission denied" when a regular user attempts to
retrieve his quota (lfs quota -u ...) but allowing him to retrieve other
users quota.

Full details at: https://jira.hpdd.intel.com/browse/LU-4530



Cc: Peng Tao <tao.peng@emc.com>
Cc: <stable@vger.kernel.org> # 3.12.x
Cc: <stable@vger.kernel.org> # 3.13.x
Signed-off-by: Cédric Dufour <cedric.dufour@idiap.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>