virt: Aexpect server logging and startup lock adjustment

* Removed possibly contentious client & server locking
  (lock-client-starting)
* Removed client dependence on server stdout
* Made server close stdin/out/err to avoid pipe flush problems
* Add support for empty reader list
* Added server logging
* Made server lock at earliest possible point
* Added exception handling to server
* Added Spawn.__init__() server timeout
* Fixed ignored exception in Spawn.__del__

Signed-off-by: Chris Evich <cevich@redhat.com>