fix Rakefile to read the version from lib/rack.rb
fix Rakefile to read the version from lib/rack.rb

imtayadeway/rack,ngpestelos/rack,deepj/rack,deepj/rack,Eric-Guo/rack,ngpestelos/rack,wjordan/rack,Eric-Guo/rack,rwz/rack,imtayadeway/rack,davydovanton/rack,rwz/rack,gioele/rack,wjordan/rack,ngpestelos/rack,imtayadeway/rack,wjordan/rack,gfvcastro/rack,gioele/rack,davydovanton/rack,rwz/rack,Eric-Guo/rack,deepj/rack,gfvcastro/rack,gfvcastro/rack,gioele/rack,davydovanton/rack