Fix tablet keyboard button draw issues

- Keyboard key presses didn't show feedback unless the key was held
  for a while
- Keyboard background image wasn't drawn

Fixes GF-4364, GF-4613

Open-webOS-DCO-1.0-Signed-off-by: Teppo Pennanen <teppo.pennanen@lge.com>

Change-Id: I2f474b194aa6ef3a3e265e9efb117a93207598e5