Fix the display of microseconds from log_timed.
Review Request #5557 — Created Feb. 27, 2014 and submitted
log_timed was formatting microseconds incorrectly, making it appear as
if operations were taking longer than they actually were. This was
because the microseconds weren't appearing zero-padded in the string.This adds the zero-padding, giving us accurate logging information.
Noticed that some timestamps made no sense. After this fix, they added up.
Unit tests pass.