Consider "undefined" device lock state equal to "unlocked"

When lipstick is restarted and device lock is not in use, ui ends
up showing lock screen instead of home. This happens initial
device lock = "undefined" is interpreted by mce as "locked".

Equate "undefined" device lock state with "unlocked" instead.

[mce] Consider "undefined" device lock state equal to "unlocked". Fixes JB#24138
Merge pull request #222 from spiiroin/jb24138_handle_undefined_device_lock_state

Consider "undefined" device lock state equal to "unlocked"