* If the user has GMS installed, they'll need to install an updated
copy, as addon.d won't restore it, and if it did it likely wouldn't
work. So we can't support this unconditionally.
* If the user has no-GMS, this should be totally fine to do, so the
user could set the property, upgrade, and go on their merry way.
This use-case is why I didn't make this an `ro.` property.
* If someone building LineageOS builds GMS into the images, upgrade
via this method would also be feasible.
Change-Id: If2a6e6767dcb182d3dbd2a95c81a940fdb53547e
Nolen Johnson
c9159bf47b