Settings: Remove "Make pattern visible" regardless.

  - Previous logic depended on all pattern lock elements to be
    null prior to removing the preferences. Remove them one by
    one if they exist now.

  - PS #3: Add braces.

Change-Id: If34bc305eddda2985b37bd55349e4bb5d9b63154
Merge "Settings: Remove "Make pattern visible" regardless." into cm-11.0