Bitcoin-Qt: emit numBlocksChanged for changed reindex or importing state

- this allows our progressbarlabel to correctly update, when we
  finish a reindex or import, but do not get new blocks from other sources

src/qt/clientmodel.h

@@ -60,6 +60,8 @@ private:
 
     int cachedNumBlocks;
     int cachedNumBlocksOfPeers;
+	bool cachedReindexing;
+	bool cachedImporting;
 
     int numBlocksAtStartup;