[8] Request for Review: 8016916: UnstructuredName should support DirectoryString

[Jason Uh]

Can I please get a review of this changeset?

Bug: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8016916
Webrev: http://cr.openjdk.java.net/~juh/8016916/webrev.00/

This change adds PrintableString to the list of ASN.1 tags that 
PKCS9Attribute accepts for the UnstructuredName attribute. Also, the 
'keytool -printcertreq' output has been enhanced because the way it was 
before, it would have printed:

   1.2.840.113549.1.9.2
   [Ljava.lang.String;@4e0e2f2a

for an UnstructuredName attribute.

Thanks,
Jason