Make Linux/Mac CIPD wrapper fail if any step returns an error.

Include the "-f" curl flag, which will cause it to error on non-200
status.

BUG=chromium:739195
TEST=local
R=iannucci@chromium.org

Change-Id: I3efea3f38c1ee322cb9d63f29819472564107ddc
Reviewed-on: https://chromium-review.googlesource.com/560723Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Commit-Queue: Daniel Jacques <dnj@chromium.org>