newpromise-708984: Use central copy of add-on promise
newpromise-708984: Use central copy of add-on promise

Signed-off-by: Joe Walker <7a17872fbb32c7d760c9a16ee3076daead11efcf@mozilla.com>

joewalker/gcli,mozilla/gcli,mozilla/gcli,joewalker/gcli,mozilla/gcli