* lib/optparse.rb (OptionParser::Completion.candidate): get rid of
nil as key names. [ruby-core:75773] [Bug #12438]
* lib/optparse.rb (OptionParser#make_switch): char class option
cannot be NoArgument, default to RequiredArgument.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55228 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
nobu