Yeah I meant .key files lolI am running 6.0.1 on my Nexus 5 and did not see the .db files. I saw the gatekeeper files as .key files
You could use your method and delete gatekeeper.pattern.key and gatekeeper.password.key with TWRP file manager or use adb like this
adb devices
adb shell
cd /data/system
rm gatekeeper.pattern.key
rm gatekeeper.password.key
Also use "sudo cd ~/data/system .
In my opinion that is a pretty huge security flaw right here [emoji1]