libbe: ui_color() now works without UI connection.

* Since the app_server is a BApplication, too, now, Workspaces would
  trigger this problem.
* Now it checks whether the shared memory is actually set, and only
  uses it in this case. This will also fix using ui_color() in any
  BServer without UI connection.

src/kits/app/Application.cpp

@@ -343,11 +343,12 @@ BApplication::_InitData(const char* signature, bool initGUI, status_t* _error)
 {
 	DBG(OUT("BApplication::InitData(`%s', %p)\n", signature, _error));
 	// check whether there exists already an application
-	if (be_app)
+	if (be_app != NULL)
 		debugger("2 BApplication objects were created. Only one is allowed.");
 
 	fServerLink = new BPrivate::PortLink(-1, -1);
 	fServerAllocator = NULL;
+	fServerReadOnlyMemory = NULL;
 	fInitialWorkspace = 0;
 	//fDraggedMessage = NULL;
 	fReadyToRunCalled = false;