GPCard: add log message

Author: promovicz

Diff for: globalplatform/src/main/java/org/openjavacard/gp/client/GPCard.java

@@ -453,6 +453,8 @@ public void disconnect() throws CardException {
      */
     private void ensureConnectedToCard() throws CardException {
         if(mCard == null) {
+            LOG.debug("connecting to card");
+
             // connect to the card
             mCard = mTerminal.connect("*");