Update em-dir-watcher.rb

Problem on deploy 

/Library/Ruby/Gems/2.0.0/gems/em-dir-watcher-0.9.4/lib/em-dir-watcher.rb:7:in `<module:EMDirWatcher>': Use RbConfig instead of obsolete and deprecated Config.
/Library/Ruby/Gems/2.0.0/gems/em-dir-watcher-0.9.4/lib/em-dir-watcher.rb:7:in `<module:EMDirWatcher>': Use RbConfig instead of obsolete and deprecated Config.


problem is solved