add assert

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@2304 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/switch_ivr.c

@@ -439,7 +439,7 @@ SWITCH_DECLARE(switch_status_t) switch_ivr_play_file(switch_core_session_t *sess
 					  comment,
 					  date);
 
-
+	assert(read_codec != NULL);
 	interval = read_codec->implementation->microseconds_per_frame / 1000;