Give enough time to connect to other instance.

When a first instance does not respond below 100 ms a second instance
assumes there is no other instance and the socket is a leftover of a
crash. This circumstance may happen when session managers autostart but
also restore albert from a former session at boot and the first instance
is simply to busy loading plugins.

src/rpcserver.cpp

@@ -50,7 +50,7 @@ RPCServer::RPCServer()
     DEBG << "Checking for a running instance…";
     QLocalSocket socket;
     socket.connectToServer(socket_path);
-    if (socket.waitForConnected(100)) {
+    if (socket.waitForConnected()) {
         INFO << "There is another instance of albert running.";
         ::exit(2);
     } else {