LU-3403 test: error of listxattr when buffer is small

LU-3403 test: error of listxattr when buffer is small

Add a new test for LU-3403. Check that when a buffer
that is too small is passed into listxattr the system
call fails correctly.

Signed-off-by: Keith Mannthey <keith.mannthey@intel.com>
Change-Id: Idf45a3155284a20afadbd2c331a3d85710f740cb
Reviewed-on: http://review.whamcloud.com/6594
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Li Xi <pkuelelixi@gmail.com>
Tested-by: Hudson
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>