MB-11644: fix logic in rebalance_out_with_ddoc_compaction

Change-Id: Id06bbb0bb0aa681f0f109f9adf9dd13394400bd3
Reviewed-on: http://review.couchbase.org/39139
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>