Add flag to hide disabled keyguard options.

Normally keyguard options are disabled by things like credential
storage and device admins, so we show the reason in ChooseLockGeneric.

However, in the case of fingerprint we want to limit the scope
to just those options that have security (pin,password,pattern).

Bug 19592835

Change-Id: I6832ff692bad538adeec2f2575fca4f8f04f40cf