Fix crash from socket creation failure in media plugin system

Author: Rye

indra/llplugin/llpluginprocessparent.cpp

@@ -400,9 +400,14 @@ void LLPluginProcessParent::idle(void)
                 apr_sockaddr_t* addr = NULL;
                 mListenSocket = LLSocket::create(gAPRPoolp, LLSocket::STREAM_TCP);
                 mBoundPort = 0;
+                if (!mListenSocket)
+                {
+                    killSockets();
+                    errorState();
+                    break;
+                }
 
                 // This code is based on parts of LLSocket::create() in lliosocket.cpp.
-
                 status = apr_sockaddr_info_get(
                     &addr,
                     "127.0.0.1",