To fix bugs in DISASTER_RECOVERY.py

[fracarnicelli]

In "DISASTER_RECOVER.PY" the management of class variable can be improved (actually a new one is created every time the method "resume_old_session" is called), and there's the need to fix the signature of "clean_current_path" method.

[GassiGiuseppe]

i'll explain it a little more, the function of disaster recovery instantiate internally the class of Settings and FolderMananger to clean the folder if the user does not want to recover the old photos not yet printed. However later the instantiation of such classes was moved in the block of the code where they are used, so they are not called every time this function runs but only when they are truly needed, this is right now a clever solution, another could be to pass down Setting and FolderManager from the Runner, but i don't think that this solution will be faster. So if for @vitodibari is all right we can close this issues right away.

[GassiGiuseppe]

ping @vitodibari @fracarnicelli

[GassiGiuseppe]

If we really want to check the "disaster" only at the start up, we can change how it behaves and moves its call in the preparation method, such decision however have to be carefully made since in my opinion it is a good practice to check that everything has gone as expected every cycle. So we have to decide, move the method or close this issue.