Fixed broken --auto-play command in pjsua

git-svn-id: https://svn.pjsip.org/repos/pjproject/trunk@964 74dad513-b988-da41-8d7b-12977e46ad98
diff --git a/pjsip-apps/src/pjsua/pjsua_app.c b/pjsip-apps/src/pjsua/pjsua_app.c
index 5d9f653..bfe0300 100644
--- a/pjsip-apps/src/pjsua/pjsua_app.c
+++ b/pjsip-apps/src/pjsua/pjsua_app.c
@@ -2953,7 +2953,7 @@
 	if (status != PJ_SUCCESS)
 	    goto on_error;
 
-	if (app_config.wav_id == 0) {
+	if (app_config.wav_id == PJSUA_INVALID_ID) {
 	    app_config.wav_id = wav_id;
 	    app_config.wav_port = pjsua_player_get_conf_port(app_config.wav_id);
 	}