This change also replace break by continue, in order to try next computer,
if others computers exist.

The tests runs always 1 test per available computer (no more
no less), this approach prevent pick several tests on the same
machine which leads to timeouts and lack of resources (Disk) on
some machines.

If a software release fail to install because it was not found, there is no
reason to tear down it.

Network can be quite unreliable, so play safe retrying the method in case
some exception related to network failure be raised. Usually they are
related to timeout on SSLError and/or xmlrpclib timeouts.

Make test agent delay more time for 2 reasons:

  - slapgrid-cp/sr takes more them 1 min to run
  - The default periodicity on the servers are 5 min, so nothing happens in
        less them 5 minutes.

This change also gives time for vifib master process the information with
activities.

This changes improve the log readability in order to identify when a test
start and stops (tears down.)

This reverts commit 7f03294b.

Conflicts:
	CHANGES.txt

Conflicts:
	CHANGES.txt
	setup.py