MB-100: more logs in swap.common_setup if reb running

Change-Id: I75cfdb12d6551e04d00bf4f6bb690b938364eb66
Reviewed-on: http://review.couchbase.org/24191
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: buildbot <build@couchbase.com>