tree-wide: Don't explicity disable copy-on-write when copying images

Since the copy helpers now copy file attributes as well, let's not
explicitly disable copy-on-write anymore when we copy an image. If
the source already has copy-on-write disabled, the copy will have it
disabled as well. Otherwise, the copy will also have copy-on-write
enabled.

This makes sure that reflinks always work as reflink is only supported
if both source and target are copy-on-write or both source and target
are not copy-on-write.

src/core/exec-invoke.c

@@ -2893,16 +2893,6 @@ static int setup_ephemeral(
                 if (fd < 0)
                         return log_debug_errno(fd, "Failed to copy image %s to %s: %m",
                                                *root_image, new_root);
-
-                /* A root image might be subject to lots of random writes so let's try to disable COW on it
-                 * which tends to not perform well in combination with lots of random writes.
-                 *
-                 * Note: btrfs actually isn't impressed by us setting the flag after making the reflink'ed
-                 * copy, but we at least want to make the intention clear.
-                 */
-                r = chattr_fd(fd, FS_NOCOW_FL, FS_NOCOW_FL, NULL);
-                if (r < 0)
-                        log_debug_errno(r, "Failed to disable copy-on-write for %s, ignoring: %m", new_root);
         } else {
                 assert(*root_directory);