GWResolver: Attempt to find host before resolving

Signed-off-by: Joe Stringer <joestringernz@gmail.com>
GWResolver: Improve code formatting

Signed-off-by: Joe Stringer <joestringernz@gmail.com>
GWResolver: Don't resolve gateways for RMT_DELETE

Signed-off-by: Joe Stringer <joestringernz@gmail.com>