LU-1571 mdt: Do not update xid for open replay req

LU-1571 mdt: Do not update xid for open replay req

Do not update last_xid for open replay req,
otherwise the following resend(after replay)
can not be matched with correct xid.

Remove unnecessary mti_transo zero check in
mdt_empty_transno.

Original Change-Id: I2a05f3ac05b301ae31641a1dc51f8c4eed96427d
Original Reviewed-on: http://review.whamcloud.com/3195
cherry-picked from 3402e6c6517cc15f159b19bf4462279285cd83f2

Change form Original:
Fixed mutex change in mdt_empty_transno()

Signed-off-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Signed-off-by: wang di <di.wang@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: I9a26b25ae88e0ae2299975ff4abce9b47289fb17
Reviewed-on: http://review.whamcloud.com/5003
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>