Fixes spacing issues in the training guides

There were a number of typo's or missing spaces
in the training guide for the associate controller
node. This patch adds them in and is a result of
LP#1278312.

Change-Id: Ia36bb22617250f4a3c7b8e0224d43e54412da53f
Closes-Bug: #1278312
Removes duplicated security for instances entry

This patch removes a duplicated section within the training
guides for setting up security and access for instances.
This was reported in LP#1278310.

Change-Id: Ibdf92ff8e1d46f8539d335a70e3700f16ef73284
Closes-Bug: #1278310
Merge "Removes duplicated security for instances entry"
Merge "Fixes spacing issues in the training guides"