Fix two unlikely memory leaks

Fix two unlikely memory leaks

In gss_krb5int_make_seal_token_v3(), one of the bounds checks (which
could probably never be triggered) leaks plain.data.  Fix this leak
and use current practices for cleanup throughout the function.

In xmt_rmtcallres() (unused within the tree and likely elsewhere),
store port_ptr into crp->port_ptr as soon as it is allocated;
otherwise it could leak if the subsequent xdr_u_int32() operation
fails.