Revert "rm-rf: Make sure we rewinddir() before readdir()"

This reverts commit 6bbb893b90.

Let's try a different approach where we make sure that all callers only pass in
a fd that is "clean", i.e. at offset 0. The majority of callers of this function
(both direct and indirect) pass a freshly-opened fd, so the rewind call is not
needed.

src/shared/rm-rf.c

@@ -365,10 +365,6 @@ static int rm_rf_children_impl(
                                                                strna(path));
                                 }
                         }
-
-                        /* Make sure we reset the iterator since we don't know the state the passed in file
-                         * descriptor is in. */
-                        rewinddir(d);
                 }
 
                 FOREACH_DIRENT_ALL(de, d, return -errno) {