EditorManager: Fix opening of editors based on editor id

Make sure the editor with the requested id will be in the
list of editors to use to open files. This unbreaks e.g.
the git submit editor which opens an empty file.

Change-Id: I51c76ae13ddf0077e895ca0a9b7797f664888c0f
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/coreplugin/editormanager/editormanager.cpp

@@ -583,8 +583,12 @@ IEditor *EditorManagerPrivate::openEditor(EditorView *view, const QString &fileN
     }
 
     EditorManager::EditorFactoryList factories = EditorManagerPrivate::findFactories(Id(), fn);
-    if (editorId.isValid())
-        std::stable_partition(factories.begin(), factories.end(), Utils::equal(&IEditorFactory::id, editorId));
+    if (editorId.isValid()) {
+        if (IEditorFactory *factory = findById<IEditorFactory>(editorId)) {
+            factories.removeOne(factory);
+            factories.push_front(factory);
+        }
+    }
 
     IEditor *editor = 0;
     auto overrideCursor = Utils::OverrideCursor(QCursor(Qt::WaitCursor));