MFC r311709:

Style(9) fixes

- Sort sys/ #includes
- Use nitems instead of hardcoding the length of `mib`

Merge an applicable subset of r263234 from HEAD to stable/10:

Update most userspace consumers of capability.h to use capsicum.h instead.

auditdistd is not updated as I will make the change upstream and then do a
vendor import sometime in the next week or two.

Note that a significant fraction does not apply, as FreeBSD 10 doesn't
contain a Capsicumised ping, casperd, libcasper, etc. When these features
are merged, the capsicum.h change will need to be merged with them.

Sponsored by: Google, Inc.

Merge an applicable subset of r263234 from HEAD to stable/10:

Update most userspace consumers of capability.h to use capsicum.h instead.

auditdistd is not updated as I will make the change upstream and then do a
vendor import sometime in the next week or two.

Note that a significant fraction does not apply, as FreeBSD 10 doesn't
contain a Capsicumised ping, casperd, libcasper, etc. When these features
are merged, the capsicum.h change will need to be merged with them.

Sponsored by: Google, Inc.