cros: Honor upload_stats attribute.
cros: Honor upload_stats attribute.

Actually pay attention to subcommands' upload_stats attribute to
determine whether to upload stats.

BUG=None
TEST=ran 'cros --log-level=debug lint <file>' and verified it wasn't
     uploading stats.  Verified 'cros chrome-sdk' is still uploading
     stats.

Change-Id: I50720d6a1f7ed049b1dce1b21e14ce021f833da7
Reviewed-on: https://gerrit.chromium.org/gerrit/48716
Reviewed-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Commit-Queue: Ryan Cui <5ce1592d53754a87a44fc2eb7b63d5f77cf50fdb@chromium.org>
Tested-by: Ryan Cui <5ce1592d53754a87a44fc2eb7b63d5f77cf50fdb@chromium.org>

chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite