core/dhcp: adjust client plugin priority

Prioritize internal, which is what most people should be using. Try
dhclient last, so that it's not attempted when not explicitly
configured or everything else fails.

src/core/dhcp/nm-dhcp-listener.c

@@ -30,18 +30,18 @@ const NMDhcpClientFactory *const _nm_dhcp_manager_factories[6] = {
 /* the order here matters, as we will try the plugins in this order to find
  * the first available plugin. */
 
+    &_nm_dhcp_client_factory_internal,
 #if WITH_DHCPCANON
     &_nm_dhcp_client_factory_dhcpcanon,
 #endif
-#if WITH_DHCLIENT
-    &_nm_dhcp_client_factory_dhclient,
-#endif
 #if WITH_DHCPCD
     &_nm_dhcp_client_factory_dhcpcd,
 #endif
-    &_nm_dhcp_client_factory_internal,
     &_nm_dhcp_client_factory_systemd,
     &_nm_dhcp_client_factory_nettools,
+#if WITH_DHCLIENT
+    &_nm_dhcp_client_factory_dhclient,
+#endif
 };
 
 /*****************************************************************************/