Use correct path for finding window title VCS topic

We need to pass the _path_ of the file to
findVersionControlForDirectory, excluding the file name.
This broke the ClearCase plugin tests, which rely on magic top level
directory length sorting behavior.

Change-Id: I93e993d9461cc571ea1ae8070eb8d465ad004b9c
Reviewed-by: Christian Stenger <christian.stenger@digia.com>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/vcsbase/vcsbaseplugin.cpp

@@ -227,7 +227,7 @@ QString StateListener::windowTitleVcsTopic(const QString &filePath)
 {
     QString searchPath;
     if (!filePath.isEmpty()) {
-        searchPath = filePath;
+        searchPath = QFileInfo(filePath).absolutePath();
     } else {
         // use single project's information if there is only one loaded.
         const QList<ProjectExplorer::Project *> projects = ProjectExplorer::SessionManager::projects();