MB-24066: Partial revert "MB-22178: Don't use opencheckpointid to determine if in...

MB-24066: Partial revert "MB-22178: Don't use opencheckpointid to determine if in backfill phase"

Revert functional changes in
Change-Id: Ia977d6bf90e54fd1ceb8db4a9088b19d94d4bc8c,
which although addressed the rollback bug described in MB-22178, caused
the bug described in MB-24066.

The tests added in Ia977d6bf90e54fd1ceb8db4a9088b19d94d4bc8c remain but
the rollback test has been disabled as it attempts a streamRequest when
the vbucket has a opendcheckpointid of 0.

The test will be re-enabled and modified with a follow-up patch that
addresses the bug described in MB-22178.

Change-Id: Ifd11c77a10e4ebe571c50e5d518403b423c3dfa5
Reviewed-on: http://review.couchbase.org/77604
Well-Formed: Build Bot <build@couchbase.com>
Reviewed-by: Dave Rigby <daver@couchbase.com>
Tested-by: Build Bot <build@couchbase.com>