MB-9694: Fix crash caused by creating two same named upr conns

When we have an upr connection with a given name and another upr
connection is made with the same name then we need to close the
first connection and allow the second one to be created.

Change-Id: I0346b70f395b3d8c29f5288ffc7ecd5cc36a7700
Reviewed-on: http://review.couchbase.org/33309
Reviewed-by: Michael Wiederhold <mike@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>