libpod: don't generate errors for createTimer etc.

Caller will just log the error which is confusing for the user. This
matches the linux non-systemd behaviour.

It would be nice to have timer support for healthcheck on FreeBSD but
the only pre-installed timer option is at which probably isn't a good
fit here.

[NO NEW TESTS NEEDED]

Signed-off-by: Doug Rabson <dfr@rabson.org>

libpod/healthcheck_unsupported.go

@@ -5,21 +5,20 @@ package libpod
 
 import (
 	"context"
-	"errors"
 )
 
 // createTimer systemd timers for healthchecks of a container
 func (c *Container) createTimer(interval string, isStartup bool) error {
-	return errors.New("not implemented (*Container) createTimer")
+	return nil
 }
 
 // startTimer starts a systemd timer for the healthchecks
 func (c *Container) startTimer(isStartup bool) error {
-	return errors.New("not implemented (*Container) startTimer")
+	return nil
 }
 
 // removeTransientFiles removes the systemd timer and unit files
 // for the container
 func (c *Container) removeTransientFiles(ctx context.Context, isStartup bool) error {
-	return errors.New("not implemented (*Container) removeTransientFiles")
+	return nil
 }