java.security.PKCS12Attribute: port class from jdk8u60

This class provides facilities to deal with attributes in entries for
PKCS12 keystores.

Test: check-ojluni-files, make droid docs, vogar PKCS12AttributeTest
Bug: 29631070
Change-Id: I8d40fe126f189d503d6df7bfa45c4763bb7cb0d1
3 files changed