Set force_snat_range parameter

Due to change 59ac254bf15bb059cca12a82c9d819c371ea5c6f merged in Juno
Nova-network checks whether network has external gateway and does
(which it has by default) and does not create SNAT rules for the instances
if list of force snat ranges is empty now.

This change sets force_snat_range to ANY network and thus
new code adds corresponding rules.

Change-Id: I339dd09543f2900cab3ba6164207e962229e4386
Closes-Bug: 1384661
Signed-off-by: Sergii Golovatiuk <sgolovatiuk@mirantis.com>
Merge "Set force_snat_range parameter"