Remove obsolete gen_wwn parameter

* Was (never) used for iblock, rdmcp and fileio creation
* Does not exist anymore in rtslib
StorageObject status include wwn and better status

* Now display "in use" or "not in use" instead of the default kernel
  activated / deactivated text
* Added the StorageOBject WWN to the status line
Initscript refuses to start if configfs exists

* An exception to this is if we detect a potential 2.x -> 3.x
  migration scenario because /sys/kernel/config/target/core has
  at least one object and the 3.x config file does not exist.
Simpler saveconfig and exit access & confirmation

* saveconfig is now available in every context, and asks for a simple
  y/n confirmation, y being the default.
* exit just call saveconfig if needed, and does not require extra
  confirmation anymore