small update for BitcoinGUI::setNumBlocks() function

- re-work code parts that check if we have a Statusbar warning
- use same variable names in the header

src/qt/bitcoingui.h

@@ -112,7 +112,7 @@ public slots:
     /** Set number of connections shown in the UI */
     void setNumConnections(int count);
     /** Set number of blocks shown in the UI */
-    void setNumBlocks(int count, int countOfPeers);
+    void setNumBlocks(int count, int nTotalBlocks);
     /** Set the encryption status as shown in the UI.
        @param[in] status            current encryption status
        @see WalletModel::EncryptionStatus