LU-1363 llite: Not held lock when calling security_d_instantiate

security_d_instantiate() could allocate momory and/or yield cpu, don't
held spin lock.

Signed-off-by: Bobi Jam <bobijam@whamcloud.com>
Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Change-Id: Ifda26573a1c371de119fa922321dc0de83fb4b57
Reviewed-on: http://review.whamcloud.com/4517
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Fan Yong <yong.fan@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>