rm: avoid bogus diagnostic for a slash-decorated symlink-to-dir

These commands would evoke an invalid diagnostic:
    $ mkdir d && ln -s d s && env rm -r s/
    rm: cannot remove 's': Too many levels of symbolic links
remove.c was stripping trailing slashes from "s/" before passing
the name to "rm".  But a trailing slash may change the semantics,
and thus should not be stripped.
* src/remove.c (rm_fts): Do not strip trailing slashes.
* tests/rm/v-slash.sh: Adapt to new expected output.
* gnulib: Update to latest, for an improved fts.c that merely
normalizes trailing slashes.
Reported by Paul Eggert in discussion of http://bugs.gnu.org/12339

NEWS

@@ -19,6 +19,10 @@ GNU coreutils NEWS                                    -*- outline -*-
   than ignoring the -d option and failing with an 'Is a directory' error.
   [bug introduced in coreutils-8.19, with the addition of --dir (-d)]
 
+  rm -r S/ (where S is a symlink-to-directory) no longer gives the invalid
+  "Too many levels of symbolic links" diagnostic.
+  [bug introduced in coreutils-8.6]
+
 ** Improvements
 
   stat and tail work better with ZFS.  stat -f --format=%T now reports the

src/remove.c

@@ -433,9 +433,6 @@ rm_fts (FTS *fts, FTSENT *ent, struct rm_options const *x)
       /* Perform checks that can apply only for command-line arguments.  */
       if (ent->fts_level == FTS_ROOTLEVEL)
         {
-          if (strip_trailing_slashes (ent->fts_path))
-            ent->fts_pathlen = strlen (ent->fts_path);
-
           /* If the basename of a command line argument is "." or "..",
              diagnose it and do nothing more with that argument.  */
           if (dot_or_dotdot (last_component (ent->fts_accpath)))

tests/rm/v-slash.sh

@@ -26,7 +26,7 @@ touch a/x || framework_failure_
 rm --verbose -r a/// > out || fail=1
 cat <<\EOF > exp || fail=1
 removed 'a/x'
-removed directory: 'a'
+removed directory: 'a/'
 EOF
 
 compare exp out || fail=1