LU-7198 clio: remove mtime check in vvp_io_fault_start()

LU-7198 clio: remove mtime check in vvp_io_fault_start()

In fault IO initialization, inode's mtime is saved, and after
getting locks, when the IO is about to start, vvp_io_fault_start()
checks the mtime's intactness.

It's a false alarm, since the timestamp from MDS could be stale,
we maintain mtime mainly on OST objects, and if the check in
vvp_io_fault_start() happens before mtime on OST objects are merged,
it will get wrong timestamp from the inode, even the timestamp it
fetched in vvp_io_fault_init() could be wrong in the first place.

This patch remove the mtime check in vvp_io_fault_start().

Signed-off-by: Bobi Jam <bobijam.xu@intel.com>
Change-Id: Iff0a7f3ae789b443927fe2f3487829f357a93a4a
Reviewed-on: http://review.whamcloud.com/19162
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>