Fix code and test related to rules version check

Fix code and test related to an incorrectly implemented
rules version check.

This meant that a device could not return the rules version
it shipped with.

Another unused (and also confusing) method and
associated test is being deleted here.

To run tests:
make -j30 FrameworksServicesTests
adb install -r -g \
  "out/target/product/angler/data/app/FrameworksServicesTests/FrameworksServicesTests.apk"
adb shell am instrument -e package com.android.server.timezone -w \
  com.android.frameworks.servicestests \
  "com.android.frameworks.servicestests/android.support.test.runner.AndroidJUnitRunner"

Test: See above.
Bug: 31008728
Change-Id: I31b55e88072dd73055cb3d8cf252be6eac920322