Upstream made a change similar to our %s change, so we don't need that
difference any more. (But they didn't seem interested in our GNU
extensions, even though they're sensible ones that just ensure symmetry
between strftime() and strptime().)
Bug: http://b/167569813
Test: treehugger
Change-Id: I1d86d69c87b51719f0583341fafa7802869cd37e