And use it so that we continue to populate the old :reloading_for_preload_upgrade field for downgrades. (This is mostly useful for downgrade compatibility)
…reloading Add switches for altering/restoring the environment on reload This adds --drop-env-var and --reexec-as, which lets a reloaded einhorn load up as if it had a fresh environment. Also, this changes `upgrade` and `upgrade_fleet` to always reload einhorn, not just on upgrades with preloaded code.
Also, extract the chunk of code where we set the new master process's environment, for OAOOification.
It's just reload_for_upgrade now that we always reload einhorn on upgrades (: