Install Guide: Enhance openSUSE/SLES Neutron install instructions

Add missing packages to install.
Start Open vSwitch by default on boot.

Change-Id: I3c0d236f324f2b8ffc3d81664b0658a5fedfdd3d
backport: havana
Closes-Bug: #1243131
Merge "Install Guide: Enhance openSUSE/SLES Neutron install instructions"