dev-install: stop bootstrapping dhcp

The dhcp package is only used in test images.  There's no reason to
force bootstrapping it all the time.  The issue related to creating
users in / is a common one and currently workedaround for everyone.

BUG=chromium:402673
TEST=precq passes
TEST=running `dev_install` on a system w/out dhcp in bootstrap still works

Change-Id: Ie73d63fcb5521468c2203a1de449716221888f35
Reviewed-on: https://chromium-review.googlesource.com/1491945
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
1 file changed