agent.sh

If $FIRST_EXECUTION is set, the added tests will force the agent to do the
update process without really updating itself (i.e. running the downloaded
update package). This is done by writting "0.0.0" to version file, restoring its
real value after the fake update process is finished.

In this way, the agent can inform the installer if some error ocurred during the
process without replacing itself.

Signed-off-by: Erik Alexandre Pucci <eap08@c3sl.ufpr.br>
Acked-by: Klismann Smoger Mottin <ksm09@inf.ufpr.br>
Signed-off-by: Josiney de Souza <josineys@c3sl.ufpr.br>