MRP-1137 utils: l_getidentity_nss segfault fix

do not expect errno to be set by nss module,
explicitly return -ENOENT.

Change-Id: Ibb40643953a87900b0c101b2c7ed7c2beaf3c2c1
Reviewed-on: http://morpheus.xyus.xyratex.com:8443/gerrit/1395
Tested-by: Jenkins
Reviewed-by: Andrew Perepechko <Andrew_Perepechko@xyratex.com>
Reviewed-by: Sergey Cheremencev <Sergey_Cheremencev@xyratex.com>
Tested-by: Alexey Malakhov <Alexey_Malakhov@xyratex.com>
Reviewed-by: Vitaly Fertman <Vitaly_Fertman@xyratex.com>