Settings: disable report button for system apps

This opens CMBugReport, and we don't want these reports. Disable the
button for better UX than the button doing nothing when clicking it.

Change-Id: I2563379e7ce49a246761c040edcb797cf112efce
Signed-off-by: Roman Birg <roman@cyngn.com>
Settings: Add stats collection preference to privacy.

Change-Id: I5007d4db5074bf13fc3410eb2a3f4cd2772f9263
Merge remote-tracking branch 'cyanogenmod/cm-12.0' into cm-12.0