staging: lustre: ldlm: evict clients returning errors on ASTs

To test proper behavior of clients returning errors on ASTs
we can induce a failure with setting OBD_FAIL_LDLM_BL_CALLBACK_NET.
Handle the new additonal case of cfs_fail_err being set as well
so that the cfs_fail_err can be sent back in a reply.

Signed-off-by: Alexey Lyashkov <alexey_lyashkov@xyratex.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5581
Xyratex-bug-id: MRP-2041
Reviewed-on: http://review.whamcloud.com/11752


Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>