b/f: in bye() don't do send_200_ack while iterating over uac_trans

send_200_ack erases the transaction, which may lead to fault when
iterating is continued

core/AmSipDialog.cpp

@@ -793,19 +793,26 @@ int AmSipDialog::bye(const string& hdrs, int flags)
     switch(status){
 
     case Disconnecting:
-    case Connected:
-        for (TransMap::iterator it=uac_trans.begin();
-	     it != uac_trans.end(); it++) {
-	  if (it->second.method == "INVITE"){
-	    // finish any UAC transaction before sending BYE
-	    send_200_ack(it->second);
-	  }
+    case Connected: {
+      // collect INVITE UAC transactions
+      vector<AmSipTransaction> ack_trans;
+      for (TransMap::iterator it=uac_trans.begin(); it != uac_trans.end(); it++) {
+	if (it->second.method == "INVITE"){
+	  ack_trans.push_back(it->second);
 	}
-	if (AmConfig::WaitForByeTransaction)
-	  status = Disconnecting;
-	else
-	  status = Disconnected;
-	return sendRequest("BYE", "", "", hdrs, flags);
+      }
+      // finish any UAC transaction before sending BYE
+      for (vector<AmSipTransaction>::iterator it=
+	     ack_trans.begin(); it != ack_trans.end(); it++) {
+	send_200_ack(*it);
+      }
+
+      if (AmConfig::WaitForByeTransaction)
+	status = Disconnecting;
+      else
+	status = Disconnected;
+      return sendRequest("BYE", "", "", hdrs, flags);
+    }
 
     case Pending:
 	status = Disconnecting;