hammerd: rename uma metrics to include cros prefix

See CL:718556 and CL:725005.

BUG=b:64195183
TEST=None

Change-Id: If91bd9ebe7f2ec1f139d68b8d5bcea74e22ea744
Reviewed-on: https://chromium-review.googlesource.com/725159
Commit-Ready: Joel Kitching <kitching@chromium.org>
Tested-by: Joel Kitching <kitching@chromium.org>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
1 file changed