Fix get_default_route() to actually return the default route (i.e. a route
that matches all destinations) rather than the first route with no gateway.
Needed to fix http://bugzilla.gnome.org/show_bug.cgi?id=503518

Index: src/backend.c
===================================================================
--- src/backend.c	(revision 127)
+++ src/backend.c	(working copy)
@@ -95,7 +95,7 @@ get_default_route(void)
 		
 		if (retval != 11) continue;
 			
-		if (gw == 0 && !is_dummy_device(device)) {
+		if (mask == 0 && !is_dummy_device(device)) {
 			fclose(fp);
 			return device;
 		}			
