Fix clearing callbacks for timeout-ed requests.

Telegram/SourceFiles/mtproto/connection.cpp

@@ -2322,7 +2322,7 @@ void ConnectionPrivate::requestsAcked(const QVector<MTPlong> &ids, bool byRespon
 			while (ackedCount-- > MTPIdsBufferSize) {
 				auto i = wereAcked.begin();
 				clearedBecauseTooOld.push_back(RPCCallbackClear(
-					i.key(),
+					i.value(),
 					RPCError::TimeoutError));
 				wereAcked.erase(i);
 			}

Telegram/SourceFiles/mtproto/mtp_instance.cpp

@@ -941,6 +941,10 @@ void Instance::Private::clearCallbacks(mtpRequestId requestId, int32 errorCode)
 		}
 	}
 	if (errorCode && found) {
+		LOG(("API Error: callbacks cleared without handling! "
+			"Request: %1, error code: %2"
+			).arg(requestId
+			).arg(errorCode));
 		rpcErrorOccured(requestId, h, internal::rpcClientError("CLEAR_CALLBACK", QString("did not handle request %1, error code %2").arg(requestId).arg(errorCode)));
 	}
 }