Spelling correction in Installation Guide

The "acontainer-server.conf" expression found in "Install and configure
storage nodes" section in OpenStack Installation Guide for Ubuntu 14.04
has been changed to "container-server.conf".

Change-Id: If5e3a664ef4e42d5e7945364ef5d4b892f38be85
Closes-Bug: #1385070
Merge "Spelling correction in Installation Guide"