Added missing "ubygems.rb" file of rubygems to LEGAL.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59993 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

LEGAL

@@ -683,7 +683,7 @@ spec/ruby:
     FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     OTHER DEALINGS IN THE SOFTWARE.
 
-lib/rubygems.rb, lib/rubygems/*, test/rubygems:
+lib/rubygems.rb, lib/ubygems.rb, lib/rubygems/*, test/rubygems:
 
   RubyGems is copyrighted free software by Chad Fowler, Rich Kilmer, Jim
   Weirich and others.  You can redistribute it and/or modify it under