MB-11873: Revert "fixed remote_clusters_info bucket gc-ing"

This reverts commit f7fe5469015fdd19fc58cf70f896d922a45daa0d.

It turns out that this fix uncovered a couple of other bugs in
xdcr. In order to quickly return xdcr back to "working" state I want
to revert this good fix first. Then fix original problems, then revert
this revert.

Change-Id: I22f0f7f895b22b22c13be579528bf82689e4cc55
Reviewed-on: http://review.couchbase.org/40269
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>