Ant integration DSL issue

[isaiah]

Rake task definition like this:

task :compile => "pkg/classes" do |t|
  ant.javac :srcdir => "java", :destdir => t.prerequisites.first,
    :source => "1.7", :target => "1.7", :debug => true
end

aborts with the following exception:

no method 'setAttribute' for arguments (org.jruby.RubySymbol,org.jruby.RubyString) on Java::OrgApacheToolsAnt::RuntimeConfigurable
  available overloads:
    (java.lang.String,java.lang.Object)
    (java.lang.String,java.lang.String)

This is because when the parameters are passed to ant, the key is passed as it is, which should be converted to String instead.