Updated nova-network to correct info given

Changed intro text, and final step, as per bug report. Slightly updated
wording and corrected bug number.

Change-Id: I91fa36d6bb1c4713f8d776e5ca71454c839f91e2
backport: havana
Closes-Bug: #1245960
(cherry picked from commit d0812cc840d9544380a3093fa42ddf507d64a711)
Merge "Updated nova-network to correct info given" into stable/havana