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>
diff --git a/fm_and_key_version_test_prep.sh b/fm_and_key_version_test_prep.sh
index 76ea9a1..182a0ea 100755
--- a/fm_and_key_version_test_prep.sh
+++ b/fm_and_key_version_test_prep.sh
@@ -203,7 +203,7 @@
 # Enable firmware update
 scripts/image_signing/tag_image.sh --from="${WORKING_DIR}/${IMAGE_NAME}" \
   --update_firmware 1
-cp tests/devkeys/* "${KEYS_DIR}"
+cp -r tests/devkeys/* "${KEYS_DIR}"
 cp scripts/keygeneration/* "${KEYS_DIR}"
 
 # Load keygeneration helper methods