Cleanup misc compilation warnings with gcc

git-svn-id: https://svn.pjsip.org/repos/pjproject/trunk@509 74dad513-b988-da41-8d7b-12977e46ad98
diff --git a/pjlib/src/pjlib-test/udp_echo_srv_ioqueue.c b/pjlib/src/pjlib-test/udp_echo_srv_ioqueue.c
index 8ede493..50db493 100644
--- a/pjlib/src/pjlib-test/udp_echo_srv_ioqueue.c
+++ b/pjlib/src/pjlib-test/udp_echo_srv_ioqueue.c
@@ -149,6 +149,7 @@
         timeout.sec = 0; timeout.msec = 10;
         rc = pj_ioqueue_poll(ioqueue, &timeout);
     }
+    return 0;
 }
 
 int udp_echo_srv_ioqueue(void)