* Do str_replace only on the $dirname variable

First: Block the poll (no more modification)
Second: Delete the poll 60 days after the expiration date (configurable)

(cherry picked from commit c15ce049)

Conflicts:
	app/classes/Framadate/Utils.php

(cherry picked from commit 6751a8a9)

Conflicts:
	adminstuds.php
	app/classes/Framadate/Utils.php
	creation_sondage.php

(cherry picked from commit e6d171a4)

Conflicts:
	app/classes/Framadate/Utils.php

Cherry-picked :
        e6d171a4

Conflicts:
	app/classes/Framadate/Utils.php