Bug 821249, fix Android WebRTC build bustage in DataChannel.cpp, r=jesup

netwerk/sctp/datachannel/DataChannel.cpp

@@ -393,7 +393,7 @@ public:
 
     memset(&addr, 0, sizeof(addr));
     addr.sconn_family = AF_CONN;
-#if !defined(__Userspace_os_Linux) && !defined(__Userspace_os_Windows)
+#if defined(__Userspace_os_Darwin)
     addr.sconn_len = sizeof(addr);
 #endif
     addr.sconn_port = htons(mConnection->mLocalPort);