Fix programlistings for common, user, config guides

The goal is to use programlisting properly and thus I added proper
language setting as appropriate and also used userinput in a few cases

Partial-Bug: #1217503

Change-Id: Ib38273845b165a0f66ea23f3bf681aa2d8712e00
Write to /dev/vdb, not /dev/null

User guide had two lines that were writing data to /dev/null. From
context, it seems clear the writes should be happening to /dev/vdb
instead.

Change-Id: I7e9e42bd7d688a78aea25cc9fa5865c411c7f154
Merge "Fix programlistings for common, user, config guides"
Merge "Write to /dev/vdb, not /dev/null"