* lib/fileutils.rb: chmod/chmod_R with a string mode (e.g., "+x")
  caused error in verbose mode.

* test/fileutils/test_fileutils.rb: add a test for above.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39011 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* ChangeLog: Forgot to add a reference to the ChangeLog of the
  previous commit.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39012 b2dd03c8-39d4-4d8f-98ff-823fe69b080e