Analyzer: Re-introduce ValgrindTool level

This partially reverts 1fb755bb42. It turns out that this is a better
place to have the valgrind specific startLocal/startRemote logic
shared by the valgrind tools.

Change-Id: I1638b6d7665db81227e0a1a9aeef1ce944449391
Reviewed-by: Aurindam Jana <aurindam.jana@digia.com>

src/plugins/valgrind/memchecktool.cpp

@@ -179,7 +179,7 @@ static void initKindFilterAction(QAction *action, const QList<int> &kinds)
 }
 
 MemcheckTool::MemcheckTool(QObject *parent)
-  : IAnalyzerTool(parent)
+  : ValgrindTool(parent)
 {
     m_settings = 0;
     m_errorModel = 0;