Add common file with shared examples for all cases
Add common file with shared examples for all cases

* Add a concept of "common" specs that can be
  included to all other specs
* Add a check that all specs don't try to run
  nova-compute service

Change-Id: If6b825df686205bac2fa537812c791c667204e97
Depends-On: https://review.openstack.org/#/c/281967/

xarses/fuel-library,stackforge/fuel-library,stackforge/fuel-library,xarses/fuel-library,stackforge/fuel-library,xarses/fuel-library,xarses/fuel-library,stackforge/fuel-library