Add some troubleshooting informations
Add some troubleshooting informations

This error could be somewhat difficult to find and as this
documentation file contains the instructions for a Quick Start
the quicker the issue is found and solved the better

Change-Id: I3c184b0af8729f00dbb15f7b5ad610645a901836

bunchc/openstack-ansible,openstack/openstack-ansible,bunchc/openstack-ansible,stackforge/os-ansible-deployment,openstack/openstack-ansible,stackforge/os-ansible-deployment