Add ssh check to quantum smoke test.

 * Doing a ping check to verify that a vm is reachable may result
   in a false positive if the target ip is routed in error to a
   nonetheless pingable host.  This patch adds an ssh check that will
   fail if the target is not configured with the expected (and
   dynamically generated) ssh keypair.
 * Adding the ssh check uncovered a bug in security group creation -
   source group rules were being used that restricted traffic to
   ports associated with the security group.  This is now fixed.
 * Addresses bug 1182343

Change-Id: I4112ad9a8854fc113d5fefc7ea03a55da7d0ed1b
Merge "Add ssh check to quantum smoke test."