(2/2)Cherry-pick before build (ported from pac-4.4 branch)

This will enable us to specify gerrit commits not yet merged
to be cherry-picked before build starts

PS1: Port to pac-4.4 branch
- Resolve inconsistent JSON responses
- Fix derp
PS2: Fix CM JSON response; update LX cherry-picks
- Fix derp
PS3: Move cherries.sh to vendor/pac
- compensate for leading zero in fetch/ref

Change-Id: Icbf657759bbe06096c6faa05388d560f0ee2ec48