Add a full example of a file-backed disk creation, I used the Handbook's example.
Add a full example of a file-backed disk creation, I used the Handbook's
example.

PR:		docs/51897
Submitted by:	Kevin Oberman <oberman@es.net>

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase