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

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

Simply things so that "#REQUIRE: FILESYSTEMS" means the file
systems are fully "ready to go".

'FILESYSTEMS' states: "This is a dummy dependency, for services which
require file systems to be mounted before starting." However, we have
'var' which is was run after 'FILESYSTEMS' and can mount /var if it
already isn't mounted. Furthermore, several scripts cannot use /var
until 'cleanvar' has done its thing. Thus "FILESYSTEMS" hasn't really
meant all critical file systems are fully usable.

The entire comment block is now spell checked this time -- I promise.

Fix comment misspelling.

Submitted by: kargl

Remove old entropy seeding after consumption initializing /dev/random PRNG.
Not doing so opens us up to replay attacks.

Submitted by: Arthur Mesh <arthurmesh@gmail.com>
Sponsored by: Juniper Networks