Use a very unlikely subnet address for Vagrant

Since 192.168.0.0/24 is very commong and might overlap with some
existing networks on your laptop, using another subnet like '42' is less
bound to happen.

Signed-off-by: Sébastien Han <sebastien.han@enovance.com>
Merge pull request #116 from leseb/use-weird-subnet-range

Use a very unlikely subnet address for Vagrant