Fix 2514479: Putting phone in car dock ignores security pattern

Don't disable the keylock pattern when the device is in car mode.
Instead it should be possible to show the lock pattern at least once
and after valid authentication it should be disabled in the system.
Since this requires additional discussion it will be moved to the
next Android release.

Change-Id: I28cddcfb6640e44a29c716b59a3d6e37e8003dca