update_chroot/build_packages: log long running commands

Add a log line showing the exact command we ran so it's easier to
triage builders.  These normally output 100's of log lines, so one
more shouldn't be a problem.

TEST=CQ passes

Change-Id: I276052b19aac2b60e6f79894593093817c32e34b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/2649358
Commit-Queue: Michael Mortensen <mmortensen@google.com>
Tested-by: Mike Frysinger <vapier@chromium.org>
Auto-Submit: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Michael Mortensen <mmortensen@google.com>
4 files changed