Deleting duplicate paras from training guides

Identity Service (Keystone) section has a sentence repeating twice.
Image Service (Glance) section has a sentence repeating twice.

Closes-Bug: #1293858, #1293859
Change-Id: Id4ef3c692478d6a86aeb2f0abbb1d666f775d712
Merge "Deleting duplicate paras from training guides"