Fix DIAL multicast registering (b/29832085)

Previously the dialserver would attempt to bind only to a specific IP
address for multicast listening. This fails in the case where there are
multiple interfaces and the one chosen is not the default interface.
Using INADDR_ANY fixes that.

Bug: 29832085
Change-Id: Ic774ec13bf7a6ac679c4f28607807178470cfb79
diff --git a/src/server/quick_ssdp.c b/src/server/quick_ssdp.c
index 7355072..253db54 100644
--- a/src/server/quick_ssdp.c
+++ b/src/server/quick_ssdp.c
@@ -156,7 +156,7 @@
   mreq.imr_multiaddr.s_addr = inet_addr("");
-  mreq.imr_interface.s_addr = inet_addr(ip_addr);
+  mreq.imr_interface.s_addr = htonl(INADDR_ANY);
   if (-1 == setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP,
                        &mreq, sizeof(mreq))) {