This makes sure that process tokens credentials with un-initialized
audit contexts are handled correctly. Currently, when invariants are
enabled, this change fixes a panic by ensuring that we have a valid
termid family. Also, this fixes token generation for process tokens
making sure that userspace is always getting a valid token.
This is consistent with what Solaris does when an audit context is
un-initialized.
Obtained from: TrustedBSD Project
MFC after: 1 week