To avoid confusion, rename the current REMOTE_PROC_DOMAIN_EVENT
message to REMOTE_PROC_DOMAIN_EVENT_LIFECYCLE. This does not
cause ABI problems, since the names are only relevant at the source
code level. On the wire they encoding is a plain integer whose
value does not change

* src/remote/remote_protocol.x: Rename REMOTE_PROC_DOMAIN_EVENT
  to REMOTE_PROC_DOMAIN_EVENT_LIFECYCLE.
* daemon/remote.c, src/remote/remote_driver.c: Update code for
  renamed event