Fix error requiring bundler/shared_helpers

Currently warbler is unusable from jruby 9.2 during to this require
failing (not sure to which extent though, but at least one spec is
failing and there's an open issue about this).

If we stop monkeypatching bundler, we don't need to require it, and thus
the error disappears. Since doing that doesn't make any tests fail, I
will assume the problems caused by not monkeypatching bundler are less
important than the problems caused by doing it.

So, I'm removing the code to fix the issue and get specs green.

Author: deivid-rodriguez

lib/warbler/templates/bundler.erb

@@ -2,18 +2,3 @@ ENV['BUNDLE_WITHOUT'] = '<%= config.bundle_without.join(':') %>'
 <% if config.bundler[:frozen] -%>
 ENV['BUNDLE_FROZEN'] = '1'
 <% end -%>
-
-module Bundler
-  module Patch
-    def clean_load_path
-      # nothing to be done for embedded JRuby
-    end
-  end
-  module SharedHelpers
-    def included(bundler)
-      bundler.send :include, Patch
-    end
-  end
-end
-
-require 'bundler/shared_helpers'