Properly handle quick switch between Home button and Gallery app

This change fixes the following bug:

1. Playing a movie (especially Full HD) by Gallery.
2. Press the Home button.
3. Press the Gallery shortcut on Launcher.
4. Very quickly repeat #2 and #3 several times.

Result: "Sorry, this video cannot be played" alert is shown.

Change-Id: Idf9d222ca1e0bb90bfe06f6dc807dfbc71b6415b
Signed-off-by: Yuriy Zabroda <yuriy.zabroda@ti.com>