LU-2237 tests: new test for re-recreating last_rcvd

LU-2237 tests: new test for re-recreating last_rcvd

To verify that the lost "last_rcvd" file can be re-created
when server mount.

Signed-off-by: Fan Yong <yong.fan@whamcloud.com>
Change-Id: Ie6d23cafc511d2a99abfc7967cafb2ae0106c18c
Reviewed-on: http://review.whamcloud.com/4397
Tested-by: Hudson
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Yu Jian <yujian@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>