Improve demand-attach fileserver bos documentation

Improve demand-attach fileserver bos documentation

Add a caution to the fileserver man page explaining that traditional
and demand-attach require different configurations, and also mention
that there are two different server implementations.  Add an example
of a bos create command for creating a demand-attach File Server to
the fileserver man page.

Add a caution to the bos create man page that a traditional fs node
won't work with demand-attach and vice versa.  Document the necessary
arguments for the dafs type.  Clarify in EXAMPLES which bos create
commands are traditional and which are demand-attach.  Add an example
of changing from a traditional to a demand-attach configuration.

Change kaserver to ptserver in the example of a simple process.

Change-Id: I4077246b69edf6e1ddc7c0761ac8e1006d471c24
Reviewed-on: http://gerrit.openafs.org/1707
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit 7d395f1754649b70311895c37962cd1770cb9f73)