- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add a very simple IPDIVERT test, which creates IP divert sockets and
checks for collision/non-collision properties in binding them. This
test would have identified a bug recently reported on current@
involding my disaggregation of the pcbinfo lock.

It would be nice if this test also exercised packet diversion and
injection, but that is for another day.

MFC after: 3 days
Sponsored by: Juniper Networks, Inc.