no need to set jruby_home anymore

lib/language_pack/ruby.rb

@@ -33,7 +33,7 @@ def default_config_vars
       "GEM_PATH" => slug_vendor_base,
     }
 
-    ruby_version_jruby? ? vars.merge("JRUBY_HOME" => slug_vendor_jruby, "JAVA_OPTS" => default_java_opts) : vars
+    ruby_version_jruby? ? vars.merge("JAVA_OPTS" => default_java_opts) : vars
   end
 
   def default_process_types
@@ -76,12 +76,6 @@ def slug_vendor_ruby
     "vendor/#{ruby_version}"
   end
 
-  # the relative path to the vendored jruby directory without the version number
-  # @return [String] resulting path
-  def slug_vendor_jruby
-    "vendor/jruby"
-  end
-
   # the absolute path of the build ruby to use during the buildpack
   # @return [String] resulting path
   def build_ruby_path
@@ -164,12 +158,6 @@ def install_ruby
     end
     error invalid_ruby_version_message unless $?.success?
 
-    if ruby_version_jruby?
-      Dir.chdir("vendor") do
-        run("ln -s #{ruby_version} jruby")
-      end
-    end
-
     bin_dir = "bin"
     FileUtils.mkdir_p bin_dir
     Dir["#{slug_vendor_ruby}/bin/*"].each do |bin|
@@ -204,7 +192,6 @@ def setup_ruby_install_env
       ENV['RBX_LIB']     = "#{build_path}/#{slug_vendor_ruby}/lib"
     end
     if ruby_version_jruby?
-      ENV['JRUBY_HOME'] = slug_vendor_jruby
       ENV['JAVA_OPTS']  = default_java_opts
     end
   end