settings: refactor QuietHours code

PatchSet: use correct context

Change-Id: I9391e274250128af5f0e9dea4bdfde2485d9a746
Quiet Hours Ringer (3/3)

Change-Id: Ia4b167654867425b8d7cac952de094b16002da02
HALO (2/2)

Change-Id: I886766e8c729904ffd54f4f3e7882ed59af1fe14