ignition/bootstrap/common: account for templated files when setting mode

The if chain just after this expects the final filename and not the
possibly templated version. Strip the suffix in case it's a templated
file.

This notably fixes the mode for `registries.conf`, which became a
templated file and so went from 0644 to 0600. This patch brings it back
to 0644.

pkg/asset/ignition/bootstrap/common.go

@@ -423,6 +423,7 @@ func AddStorageFiles(config *igntypes.Config, base string, uri string, templateD
 	}
 
 	filename := path.Base(uri)
+	filename = strings.TrimSuffix(filename, ".template")
 	parentDir := path.Base(path.Dir(uri))
 
 	var mode int