The heartbeat handler was returning cmd=abort for FailedHolding, which
caused the agent's heartbeat goroutine to exit after ~10s in hold.
Subsequent state changes (Cancel -> reboot, Override -> retry_stage)
then had no recipient, so the host sat idle at the SSH hold prompt
forever. Narrowed cmd=abort to StateReleased only; FailedHolding falls
through to cmd=continue so the loop keeps polling and can receive the
operator's eventual command.
josh
73f727b4c1