If a reload fails, clear Einhorn::State.reloading_for_preload_upgrade.
If a reload fails, clear Einhorn::State.reloading_for_preload_upgrade.

If a reload failed, this was causing further SIGALRMs to not bother
reloading, since they thought we were already doing so. In conjunction
with preloading, this meant we would never upgrade our workers.

stripe/einhorn,stripe/einhorn