Continue GCing other repos on error in one repo (#22422)

The current code propagates all errors up to the iteration step meaning
that a single malformed repo will prevent GC of other repos.

This PR simply stops that propagation.

Fix #21605

Signed-off-by: Andrew Thornton <art27@cantab.net>

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: John Olheiser <john.olheiser@gmail.com>

services/repository/check.go

 				return db.ErrCancelledf("before GC of %s", repo.FullName())
 			default:
 			}
-			return GitGcRepo(ctx, repo, timeout, args)
+			// we can ignore the error here because it will be logged in GitGCRepo
+			_ = GitGcRepo(ctx, repo, timeout, args)
+			return nil
 		},
 	); err != nil {
 		return err
 	stdout, _, err = command.RunStdString(&git.RunOpts{Timeout: timeout, Dir: repo.RepoPath()})
 
 	if err != nil {
-		log.Error("Repository garbage collection failed for %v. Stdout: %s\nError: %v", repo, stdout, err)
+		log.Error("Repository garbage collection failed for %-v. Stdout: %s\nError: %v", repo, stdout, err)
 		desc := fmt.Sprintf("Repository garbage collection failed for %s. Stdout: %s\nError: %v", repo.RepoPath(), stdout, err)
 		if err := system_model.CreateRepositoryNotice(desc); err != nil {
 			log.Error("CreateRepositoryNotice: %v", err)
 		}
 		log.Trace("Deleting %d/%d...", repo.OwnerID, repo.ID)
 		if err := models.DeleteRepository(doer, repo.OwnerID, repo.ID); err != nil {
-			log.Error("Failed to DeleteRepository %s [%d]: Error: %v", repo.FullName(), repo.ID, err)
+			log.Error("Failed to DeleteRepository %-v: Error: %v", repo, err)
 			if err2 := system_model.CreateRepositoryNotice("Failed to DeleteRepository %s [%d]: Error: %v", repo.FullName(), repo.ID, err); err2 != nil {
 				log.Error("CreateRepositoryNotice: %v", err)
 			}