Enable FLAG_SECURE for userdebug builds as well on keyguard

* We usually do "userdebug" builds, it is better to disable this.

* Leave it enabled for "eng" builds.

Change-Id: I1a63a9e95fc9e776dcdf84faccfdb42bb7de6d8b
Signed-off-by: Saalim Quadri <danascape@gmail.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>