Use Utils::Storage instead of QVariantMap in a few places

Change-Id: I02833cf2bc3caaadc22ff93ae530e4aebe4c3868
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/plugins/clangcodemodel/clangdlocatorfilters.cpp

@@ -192,7 +192,7 @@ LocatorMatcherTask currentDocumentMatcher()
     };
 
     const Group root {
-        Storage(resultStorage),
+        Tasking::Storage(resultStorage),
         CurrentDocumentSymbolsRequestTask(onQuerySetup, onQueryDone),
         AsyncTask<void>(onFilterSetup)
     };