Refactoring before changing behavior

This commit changes the Errors class to be more involved in flow
control and updates the two users accordingly.

It also renames some long variable names and contains other tidy ups.

Bug: 155738410
Test: Ran update-tzdata.py
Change-Id: If4eee63b144d9b64d41da400f3296f28b2752cd2
6 files changed