- Copy stable/10@285827 to releng/10.2 in preparation for 10.2-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.2.
- Update default pkg(8) configuration to use the quarterly branch.[1]

Discussed with: re, portmgr [1]
Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r256777-256779,256788:
Add driver for POWER hypervisor interpartition ethernet.

Approved by: re (glebius)

Add initial driver for POWER hypervisor interpartition ethernet. This is
sufficient to pass traffic but needs some more work before merging to
STABLE.