- Copy stable/10@296371 to releng/10.3 in preparation for 10.3-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.3.
- Update default pkg(8) configuration to use the quarterly branch.

Approved by: re (implicit)

MFC r272027:

Hardware driver update from Mellanox Technologies, including:
- improved performance
- better stability
- new features
- bugfixes

Supported HCAs:
- ConnectX-2
- ConnectX-3
- ConnectX-3 Pro

NOTE:
- TSO feature needs r271946, which is not yet merged.

Sponsored by: Mellanox Technologies
Approved by: re, glebius

Hardware driver update from Mellanox Technologies, including:
- improved performance
- better stability
- new features
- bugfixes

Supported HCAs:
- ConnectX-2
- ConnectX-3
- ConnectX-3 Pro

Sponsored by: Mellanox Technologies
MFC after: 1 week