Add "Turn WiFi off" action to "Open networks" notification

Forward ported to kitkat

Squashed:
add "Turn Wi-Fi off" action to the "open networks available" notification
add missing xhdpi turn wifi off image
WiFi open network notification: fix potential crash

Change-Id: I416a129388074c616892f6266af7005b4da1a521
Signed-off-by: Rohan Mathur <rohanmathur34@gmail.com>
Merge "Add "Turn WiFi off" action to "Open networks" notification" into kitkat