Fix --acl / -a typo.
Fix --acl / -a typo.

The argument to this script is named -a, not --acl.

BUG=none
TBR=build breaker
TEST=unit tests, pyflakes

Change-Id: I7df44f732e17ca23a401e615c54d8b400034a0a7
Reviewed-on: http://gerrit.chromium.org/gerrit/4524
Reviewed-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Tested-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>

coreos/chromite,chadversary/chromiumos.chromite,chadversary/chromiumos.chromite,zhang0137/chromite,bpsinc-native/src_third_party_chromite,coreos/chromite,zhang0137/chromite,coreos/chromite,bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite,zhang0137/chromite