Failed to generate payload due to error trying to cp a directory

- add -r to cp tests/devkeys to include copying tests/devkeys/android

BUG=chrome-os-partner:56279
TEST=manually execute during key increment test.

Change-Id: I6d71db93375af031193344f87f198dbd48d90a1f
Reviewed-on: https://chromium-review.googlesource.com/373200
Commit-Ready: danny chan <dchan@chromium.org>
Tested-by: danny chan <dchan@chromium.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Victor Hsieh <victorhsieh@chromium.org>
1 file changed