- 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 r261894: move devd rules for zfs events into a separate file

... and fix stale event types

move devd rules for zfs events into a separate file and fix stale event types

Also, extend with some new events.
Additionally, tag syslog messages with 'ZFS' instead of using explicit "ZFS: "
prefix in the messages themselves.

Tested by: Daniel O'Connor <doconnor@gsoft.com.au>
MFC after: 8 days
Sponsored by: HybridCluster