Settings: Fix SecuritySettings filtering.

  Recent changes to SecuritySettings to appease
  CTSVerifier expectations broke filtration for
  the lockscreen intent (would always default as
  external type). This patch also addresses the
  "Installed Blocked" settings intent filter
  not including the unknown sources checkbox.

Change-Id: If6ef7a3913ad90f4d018b26f6c3166fe47d2865a
TICKET: CYNGNOS-2171
(cherry picked from commit ab4baeed)