try to fix possible null codec issue

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@12975 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/endpoints/mod_opal/mod_opal.cpp

@@ -1144,7 +1144,6 @@ PBoolean FSMediaStream::Open()
                                        m_switchCodec->implementation->samples_per_packet,
                                        switch_core_session_get_pool(m_fsSession)) != SWITCH_STATUS_SUCCESS) {
                 switch_core_codec_destroy(m_switchCodec);
-                m_switchCodec = NULL;
                 return false;
             }
         } else {
@@ -1172,11 +1171,6 @@ PBoolean FSMediaStream::Close()
     if (!IsOpen())
         return false;
     
-    /* forget these FS will properly destroy them for us */
-
-    m_switchTimer = NULL;
-    m_switchCodec = NULL;
-
     return OpalMediaStream::Close();
 }
 
@@ -1261,6 +1255,10 @@ switch_status_t FSMediaStream::read_frame(switch_frame_t **frame, switch_io_flag
         return SWITCH_STATUS_FALSE;
     }
 
+    if (!switch_core_codec_ready(m_switchCodec)) {
+        return SWITCH_STATUS_FALSE;
+    }
+
     //switch_core_timer_step(&m_switchTimer);
 
     m_readFrame.buflen = m_readRTP.GetSize();