LU-971 mdt: fix open resent issue with last_xid

LU-971 mdt: fix open resent issue with last_xid

req_xid_is_last() compares xid with one in client data,
but in master it is not updated in case of open without create.
Patch updates export lcd with last xid, transno and rc for open
requests.

Signed-off-by: Mikhail Pershin <tappro@whamcloud.com>
Change-Id: I9e769fecc1e93c7a556d4b9eeadc80a70369e901
Reviewed-on: http://review.whamcloud.com/1930
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Yu Jian <yujian@whamcloud.com>
Reviewed-by: Li Wei <liwei@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>