Fixing build problem introduced by removing encryption jars

...s

When merging changes to the build.xml, I accidentally included some
early experimentation that didn't get rolled back.  Fixing the issue by
reverting the compile-jruby target to its original form.

Please  note that the original changes to antlib/dist.xml should accompany this.  I can't quite figure out what Github is doing here, but my intention is for the diff shown here to be applied to the code in my original pull request yesterday.

Very sorry for the churn!