LU-10992 llite: decrease sa_running if fail to start statahead

LU-10992 llite: decrease sa_running if fail to start statahead

Otherwise the counter of ll_sb_info::ll_sa_running will leak as
to the umount process will be blocked for ever.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: I6b3a0dfb39f120a0c58184a22211b52376b41bd9
Reviewed-on: https://review.whamcloud.com/32287
Tested-by: Jenkins
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>