properly tear down on a restart.

git-svn-id: http://svn.openzap.org/svn/openzap/trunk@411 a93c3328-9c30-0410-af19-c9cd2b2d52af

libs/freetdm/src/zap_isdn.c

@@ -327,8 +327,9 @@ static __inline__ void state_advance(zap_channel_t *zchan)
 		break;
 	case ZAP_CHANNEL_STATE_RESTART:
 		{
-			zap_set_state_locked(zchan, ZAP_CHANNEL_STATE_DOWN);
-			zap_channel_close(&zchan);
+			if (zchan->last_state > ZAP_CHANNEL_STATE_HANGUP) { 
+				zap_set_state_locked(zchan, ZAP_CHANNEL_STATE_HANGUP);
+			}
 		}
 		break;
 	case ZAP_CHANNEL_STATE_PROGRESS_MEDIA: