LU-8446 llite: clear inode timestamps after losing UPDATE lock

LU-8446 llite: clear inode timestamps after losing UPDATE lock

Otherwise, those leftovers would interfere with new timestamps
especially when the timestamps are set back in time on the other
clients.

Test-Parameters: alwaysuploadlogs mdtfilesystemtype=ldiskfs mdsfilesystemtype=ldiskfs ostfilesystemtype=ldiskfs mdtcount=1 testlist=metadata-updates,metadata-updates
Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Change-Id: If4d385c82b2035c08276b9dd5cd8edd029a8c027
Reviewed-on: http://review.whamcloud.com/22623
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>