Fix exception namespace

* lib/fileutils.rb (remove_entry_secure): EISDIR is under the
  Errno namespace.  [ruby-core:91362] [Bug #15577]

From: Tietew (Toru Iwase) <tietew@tietew.net>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66972 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

Author: nobu

lib/fileutils.rb

@@ -697,7 +697,7 @@ def remove_entry_secure(path, force = false)
         f.chown euid, -1
         f.chmod 0700
       }
-    rescue EISDIR # JRuby in non-native mode can't open files as dirs
+    rescue Errno::EISDIR # JRuby in non-native mode can't open files as dirs
       File.lstat(dot_file).tap {|fstat|
         unless fu_stat_identical_entry?(st, fstat)
           # symlink (TOC-to-TOU attack?)

test/fileutils/test_fileutils.rb

@@ -740,7 +740,15 @@ def test_remove_entry_secure
     remove_entry_secure 'tmp/tmpdir/c', true
     assert_file_not_exist 'tmp/tmpdir/a'
     assert_file_not_exist 'tmp/tmpdir/c'
+
+    File.chmod(01777, 'tmp/tmpdir')
+    Dir.mkdir 'tmp/tmpdir/d', 0
+    assert_raise(Errno::EACCES) {remove_entry_secure 'tmp/tmpdir/d'}
+    File.chmod 0777, 'tmp/tmpdir/d'
+    Dir.rmdir 'tmp/tmpdir/d'
+
     Dir.rmdir 'tmp/tmpdir'
+
   end
 
   def test_remove_entry_secure_symlink