Adds VM connectivity check after advanced VM operations

The advanced VM operations are:
   * Stop/Start an instance
   * Reboot an instance
   * Rebuild an instance
   * Pause/Unpause an instance
   * Suspend/Resume an instance
   * Resize an instance

This is a proposal for a tempest network scenario
aimed at validating VM connectivity after advanced
VM operations.

Partially Implements: blueprint neutron-advanced-scenarios

Change-Id: If9e658147a1fe89e3681f1309e863b901d282447
Merge "Adds VM connectivity check after advanced VM operations"
Merge commit 'refs/changes/65/81565/2' of git://gold.eng.hq.xensource.com/git/github/openstack/tempest into tmpbranch