rbuninstall.rb: rmdir -p

* tool/rbuninstall.rb: remove parent directories.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42931 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
rbuninstall.rb: tty

* tool/rbuninstall.rb: show progress if tty and add --tty option.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42932 b2dd03c8-39d4-4d8f-98ff-823fe69b080e