MB-9970: allow to close XDCR Errors dialog on escape

Change-Id: I81f547b0a1bbd3f8d53c03acbcc6ae5cb2e097c7
Reviewed-on: http://review.couchbase.org/33533
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>