krb5: return KRB5KRB_AP_ERR_INAPP_CKSUM if PAC checksum fails
Return KRB5KRB_AP_ERR_INAPP_CKSUM instead of EINVAL when verifying a PAC, if
the checksum is absent or unkeyed.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14642
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14881
[jsutton@samba.org Cherry-picked from Heimdal commit
c4b99b48c4b18f30d504b427bc1961d7a71f631e]
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
(cherry picked from commit
d6a472e953545ec3858ca969c1a4191e4f27ba63)