LU-5581 ldlm: evict clients returning errors on ASTs

LU-5581 ldlm: evict clients returning errors on ASTs

When a client returns an error other then EINVAL replying to blocking
ast, it is unsafe to cancel the lock on server side only, because the
client may continue its I/O assuming it still owns the lock while the
real lock may be granted already to another client.

In only valid error case when client replied to AST with EINVAL cancel
the lock and return ERESTART, evict the client in any other error
case.

Xyratex-bug-id: MRP-2041
Signed-off-by: Alexey Lyashkov <alexey_lyashkov@xyratex.com>
Change-Id: Ibce60ce3b2c24ba388155ac49cba8f20388893e7
Reviewed-on: http://review.whamcloud.com/11752
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>