Only disable pie on lockscreen if lockscreen is secure

allows users to acess notifications and quick tiles from the lockscreen
and still be secure. following aosp behavior

Change-Id: I8addbc958ec4e3211f9916b3428d3e3486b1c5a3
Merge branch 'jellybean' of github.com:ParanoidAndroid/android_frameworks_base into jellybean
Merge remote-tracking branch 'pa/jellybean' into fjpa