Import MIT KRB5 1.16.

2018-04-03T19:36:00+00:00

Import MIT KRB5 1.15.1, which will gracefully replace KTH Heimdal.

2017-07-07T17:03:42+00:00

The tarball used in this import is the same tarball used in
ports/krb5-115 r435378.

Obtained from:	http://web.mit.edu/kerberos/dist/
Thanks to:	pfg (for all your tireless behind-the-scenes effort)

src/doc/html/appdev/refs/api/krb5_cc_remove_cred.html, branch vendor/krb5/1.16

Import MIT KRB5 1.16.

Import MIT KRB5 1.15.1, which will gracefully replace KTH Heimdal.