refactored FileDoesNotExist(Exception)

Signed-off-by: bob_boulot <bob_boulot@daribouca.net>
comented unused code & went for more specific Exception

Signed-off-by: bob_boulot <bob_boulot@daribouca.net>
added FileDoesNotExists + stub for tempdir_can't_remove

Signed-off-by: bob_boulot <bob_boulot@daribouca.net>