Return only new keys in randkey [CVE-2014-5351]

In kadmind's randkey operation, if a client specifies the keepold
flag, do not include the preserved old keys in the response.

CVE-2014-5351:

An authenticated remote attacker can retrieve the current keys for a
service principal when generating a new set of keys for that
principal.  The attacker needs to be authenticated as a user who has
the elevated privilege for randomizing the keys of other principals.

Normally, when a Kerberos administrator randomizes the keys of a
service principal, kadmind returns only the new keys.  This prevents
an administrator who lacks legitimate privileged access to a service
from forging tickets to authenticate to that service.  If the
"keepold" flag to the kadmin randkey RPC operation is true, kadmind
retains the old keys in the KDC database as intended, but also
unexpectedly returns the old keys to the client, which exposes the
service to ticket forgery attacks from the administrator.

A mitigating factor is that legitimate clients of the affected service
will start failing to authenticate to the service once they begin to
receive service tickets encrypted in the new keys.  The affected
service will be unable to decrypt the newly issued tickets, possibly
alerting the legitimate administrator of the affected service.

CVSSv2: AV:N/AC:H/Au:S/C:P/I:N/A:N/E:POC/RL:OF/RC:C

[tlyu@mit.edu: CVE description and CVSS score]

ticket: 8018 (new)
target_version: 1.13
tags: pullup
Fix minor memory leak in klist (again)

Commit 6e51f9cc3152c8e419fe7f459bcf521d60358434 attempted to fix two
minor memory leaks in klist, but one of the fixes was dead code.  In
do_ccache, free princ before we look at the code which terminated the
loop, not after we have returned on either branch.
Use gssalloc_malloc for GSS error tokens

In kg_accept_krb5, use gssalloc_malloc when allocating space for the
error token, since it will be freed with gssalloc_free.  Using malloc
can cause heap corruption on Windows.  This bug was masked by #1445
before 1.12.

ticket: 8024 (new)
target_version: 1.13.1
tags: pullup
Document that newer AFS supports stronger crypto

Modern OpenAFS releases support using encryption stronger than single
DES with Kerberos.  Update the documentation accordingly.

ticket: 7761
target_version: 1.13
tags: pullup