builds_packages: Line wrap long DEFINE_boolean line.

This is followup from
https://crrev.com/c/2775837/1/build_packages#77

BUG=chromium:945003
TEST=./build_packages --board eve --skip_setup_board

Change-Id: Ied7a2e4db247c1ba229958c8775ccaed9d094433
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/2817912
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Michael Mortensen <mmortensen@google.com>
1 file changed