Add flag to disable call to 'eclean'.

When triaging errors via bisecting good/bad packages, we need
build_image to NOT call eclean, or it messes up our bisecting
process.  Previously we've been manually editing the build_image
script to disable the call to eclean.  This CL adds a flag to do
this instead.

BUG=chromium:455306
TEST=Tested building images with & without flag.  Both cases worked
correctly.

Change-Id: I05302b06635f8be516e84d5e27c54ad947dafbe3
Reviewed-on: https://chromium-review.googlesource.com/344570
Commit-Ready: Caroline Tice <cmtice@chromium.org>
Tested-by: Caroline Tice <cmtice@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed