Fixes some bugs in TimeZoneUtils

TimeZoneUtils was updating the db and modifying the selection. This
creates a static selection for each update type and creates new
values for each update. Also adds a method for apps to force the
local tz cache to refresh if they think another app has modified
the db.

Change-Id: Iaaade635ac8ff11bb116005a0f6b44efcd4c4056