Cleaned up and made revisions to doc

The letter "a" should not go before a vowel.
"An" goes before the word that starts with a vowel.
 The word in this case was "OpenStack".
I also added the plural version for IP Addresses.
Since we are referring to multiple IP Addresses,
we need to make sure we add "addresses" after IP.
also removed additional white space before colon

Change-Id: Ibd20045ffb83f1527007b3b4cef4763b305f724f
Merge "Cleaned up and made revisions to doc"