* tool/rbinstall.rb: skip installing bundle gems if zlib is unavailable.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49015 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* ChangeLog: mention the ticket for r49015.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49016 b2dd03c8-39d4-4d8f-98ff-823fe69b080e