Use volume keys to toggle ringer mode (1/2)

PS4: Fix build, make variable name nicer :D
PS5: autorship

Change-Id: Iea63e34ec61a08d72f62a7ec0676e7bf4799689a
GlobalActions: Set the initial status of airplane mode toggle

Actually, the initial status of airplane mode toggle is set to false
when the power menu dialog is initialized.
This causes an issue if you set airplane mode and then reboot.
After the reboot, the dialog displays the wrong airplane mode status,
eg. "Airplane mode is not active", and if you toggle that option, a wrong
intent is sent again to put ON the airplane mode, instead of OFF, the
toggle (that is in transition state) will be set disabled.

This commit fixes this issue.

Change-Id: Id30355c1e090355645c437086c79ab59093c27a8