* tool/rbinstall.rb:
- Install .gemspecs of default gem to
#{GEM_HOME}/specifications/default/.
- Update files parameter of .gemspecs by relative path from
library directory.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38053 b2dd03c8-39d4-4d8f-98ff-823fe69b080e