lets default to zero

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@11471 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/endpoints/mod_portaudio/mod_portaudio.c

@@ -919,6 +919,10 @@ static switch_status_t load_config(void)
 		globals.codec_ms = 20;
 	}
 
+	if (!globals.dual_streams) {
+		globals.dual_streams = 0;
+	}
+
 	if (!globals.ring_interval) {
 		globals.ring_interval = 5;
 	}