Clean patches directory

Make sure the directory has exactly what
we asked for.

Signed-off-by: Martin Abente Lahaye <martin.abente.lahaye@gmail.com>
Use Lookup error

Signed-off-by: Martin Abente Lahaye <martin.abente.lahaye@gmail.com>
Handle exceptions properly

Propagate information through exceptions.

Signed-off-by: Martin Abente Lahaye <martin.abente.lahaye@gmail.com>