Fix NINJA_STATUS %e on dumb terminals

PR #999 made dumb terminals only output when edges
finish. BuildStatus::overall_rate_ stopwatch is only initialized to the
current time when PrintStatus is called with finished_edges_ == 0, but
on a dumb terminal it will be called for the first time when
finished_edge_ = 1, which results in very long elapsed times:
NINJA_STATUS="[%r processes, %f/%t @ %o/s : %es ] "
[0 processes, 2/2 @ 0.0/s : 1461869902.367s ]

Reset the stopwatches in BuildEdgeFinished before finshed_edges_ is
incremented instead.

0 files changed, 0 insertions, 0 deletions