JCBC-198: Update ConfigurationProvider on reconfigure.

When a reconfiguration is needed, this changeset makes
sure the new bucket instance is populated to the
ConfigurationProvider as well (not just to the node
locator), because some code of the stack - especially
observe - depends on it. This prevents the usage of
an outdated map leading to IndexOutOfBound exceptions.

Change-Id: Ic1ab87a1502ec4f72cf003bee786d07f263abdfa
Reviewed-on: http://review.couchbase.org/24818
Reviewed-by: Matt Ingenthron <matt@couchbase.com>
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>