Fix for text-controller.

* The text disappears if the predictive text is disabled
  and a long press is done over a word.

  The problem is that in this use case a key event with
  no key code arrives, the text-controller calls the
  InsertText() method which clears the selected text.

  The fix is do nothing when this keycode arrives.

Change-Id: I23e96691fe45858165ee8fbb8695924a96a9941a
Signed-off-by: Victor Cebollada <v.cebollada@samsung.com>