PrivacyGuard: add missing @hides to method definitions

Causing DroidDoc compile errors, this fixes it by adding
a @hide to the respective function definitions.

Change-Id: I27675cd6a75fcc1535c812566e5b9098b11335e1
Merge pull request #5 from CyanogenMod/cm-11.0

PrivacyGuard: add missing @hides to method definitions