Handle exceptions when deleting networks and ports with NVP

- if network/port doesn't exist in NVP anymore, delete from quark db
- if network/port does exist in NVP, delete from quark db and then add
  info about it to new orphaned db tables for clean-up by sysadmins later

RM6485
In a statically typed language, this wouldn't work as the types of the function arguments would be different for the subclass's implementation, `lswitch_uuid` versus `switch` argument. Perhaps, name the function here something else? How do you feel?