log more things about xdcr-over-upr initialization

In order to diagnose bugs easier.

Change-Id: If91508b64f37638fd2520533f044dadc5c4c8485
Reviewed-on: http://review.couchbase.org/35532
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Artem Stemkovski <artem@couchbase.com>