LU-2494 tests: obdfilter/*/mds_sync: Found no match

Revise test-framework to look for new variable *osp*/old_sync_processed
instead of obsolete variable */mds_sync.

Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Change-Id: Ie219f17fae3b49caf52394aff16a6b7d58840ade
Reviewed-on: http://review.whamcloud.com/4885
Reviewed-by: Minh Diep <minh.diep@intel.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>