upload_prebuilts: keep track of matched packages

We hit a bug where upload_prebuilts was told to upload some packages, but
couldn't find them.  It silently ignored them making it hard to notice.

Have the code keep track of all matched packages and if there are any that
we requested but didn't match, warn about it.

BUG=chromium-os:38296
TEST=`./scripts/upload_prebuilts_unittest.py` passes
TEST=`./upload_prebuilts --build-path ~/chromiumos/ --board daisy --upload gs://chromeos-throw-away-bucket/vapier --packages foooo` warns about missing foooo package
TEST=`cbuildbot daisy-release` did not warn in DevInstallerPrebuilts stage

Change-Id: Ifb31869b6adf4062d4f53d947e2c145c75ea778a
Reviewed-on: https://gerrit.chromium.org/gerrit/43104
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed