- 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: r281324

- ggatel.8 currently doesn't mention the 'rescue' command and
documents a non-existing 'attach' command instead.
- while here address a spelling error

Approved by: wblock (mentor)
Differential Revision: https://reviews.freebsd.org/D2346

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

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

Because ggatel(8) operates on local GEOM providers, use unlimited queue size in
GEOM GATE to fix the issue described in r220264. This also means that we no
longer need -q option, remove it. Don't bother to leaving it as a no-op, as
ggatel(8) is just an example utility.

Sort sections.

Added the EXIT STATUS section where appropriate.

Polish the mdoc(7) markup.

Add missing commands.

GEOM Gate local control utility.