[Swan-dev] ikev2: use struct child_sa in ikev2_rekey_child_copy_ts(); failure isn't a real option

[D. Hugh Redelmeier]

| commit 1078374fd4fba79bb0ba5e9aa1751b2f021a1be8
| Author: Andrew Cagney <cagney at gnu.org>
| Date:   Mon Jun 3 10:04:03 2019 -0400
| 
|     ikev2: use struct child_sa in ikev2_rekey_child_copy_ts(); failure isn't a real option
|     
|     Only call when rekeying.  Replace MD parameter with CHILD.  Return
|     bool.  Use (new) child_sa_by_serialno() to find the old CHILD.
|     pexpect(old CHILD) since there not being one is a screw up
|     (resolves ???).

The ??? resolved was on code where we generated a broken notify:

- /* ??? RFC 7296 3.10: this notify requires protocol and SPI! */

Does that mean that we can re-install the pexpects in the notify emitting
code that ensured protocol and SPI were present in exactly those
notifications that require it?

The pexpect was introduced in b858f9398aa5e9552b345ecea11f970774e7a8b6
and replaced in 1897df99170a99f1d4ddef4d47689cb67488d4b4