Fix androidannotations.log in apt folder

A quick fix for [the issue](https://github.com/excilys/androidannotations/pull/1110#issuecomment-67879129) raised by @WonderCsabo.
It is called for each test. And since we keep a static reference of the `Logger`, it is called multiple times.
I don't think it is the real issue but a (ugly) workaround.