* lib/fileutils.rb: handle ENOENT error with symlink targeted to

non-exists file. [ruby-dev:45933] [Bug #6716]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46783 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/fileutils/test_fileutils.rb

@@ -445,6 +445,12 @@ class TestFileUtils < Test::Unit::TestCase
     assert_raise(Errno::ELOOP) {
       mv 'tmp/symlink', 'tmp/symlink'
     }
+    # unexist symlink
+    File.symlink 'xxx', 'tmp/src'
+    assert_nothing_raised {
+      mv 'tmp/src', 'tmp/dest'
+    }
+    assert_equal true, File.symlink?('tmp/dest')
   end if have_symlink?
 
   def test_mv_pathname