* gnu/services/shepherd.scm (<shepherd-service>): Add respawn-limit and
respawn-delay.
(shepherd-service-file): Emit the two values into the shepherd service
constructor form.
Change-Id: I54408e8fb4bcc0956d9610771bf5c566fdc2914c
Signed-off-by: Ludovic Courtès <ludo@gnu.org>