Moved setting the flag to suppress face unlock during a phone call

Moved the check to suppress face unlock if a call is in progress from
onScreenTurnedOff() to initializeBiometricUnlockView().  onScreenTurnedOff()
is only called if the screen was turned off while on lockscreen and we
actually want to be doing this every time the screen is turned off.  Put a
check around it to only do it when the screen is off, so that for orientation
changes, or on first boot it doesn't override the current flag value.

This fixes the following 2 bugs:

Bug 6460309: When making a phone call, after the user hangs up and it goes
to lockscreen we don't want face unlock to show.  In the case where a
user makes an outgoing call and the phone goes to sleep by itself during
the phone call, when the call is ended face unlock was popping up because
it never went through onScreenTurnedOff().

There is a flag to make sure face unlock doesn't come up
immediately after booting the phone, which is done by not showing
face unlock the first time lockscreen is constructed.  But there are
a few cases where lockscreen doesn't come up immediately after boot: 1. When
the device is factory reset, it goes through the wizard instead of
lockscreen.  2. In userdebug if the lock type is set to none.
In both of these cases, if face unlock is set up, it doesn't show up on
the first time.  Setting the phone flag in initializeBiometricUnlockView
overrides the initial setting, which is what we want because if the screen
has turned off, it isn't the initial lockscreen after boot.

Change-Id: Iacafc515f2b594e12c853308c40cd48f3fb83e63