MEDIUM: log-forward: use "dgram-bind" instead of "bind" for the listener

The use of "bind" wasn't that wise but was temporary. The problem is that
it will not allow to coexist with tcp. Let's explicitly call it "dgram-bind"
so that datagram listeners are expected here, leaving some room for stream
listeners later. This is the only change.
diff --git a/src/log.c b/src/log.c
index e8b172d..984a31a 100644
--- a/src/log.c
+++ b/src/log.c
@@ -3610,7 +3610,7 @@
 		px->id = strdup(args[1]);
 
 	}
-	else if (strcmp(args[0], "bind") == 0) {
+	else if (strcmp(args[0], "dgram-bind") == 0) {
 		int cur_arg;
 		static int kws_dumped;
 		struct bind_conf *bind_conf;