This method from joda-time supports replacing the system time provider
with a custom provider for tests. Since it is verbose, and we expect
more related methods, put it in the more succinct TimeUtil.nowMs().
This commit covers the trivial cases in the server side; client-side
code still uses System.currentTimeMillis().
Change-Id: I6c56e8c5bbb0cf7b0271e431d1ebdb532967b9e8
