circumvent destruction of ::policy_checker, remove destructors that are empty or...

circumvent destruction of ::policy_checker, remove destructors that are empty or never called

Motivated by KONA bugs (ex. DF161028-00875). VD product environment
apparently likes calling libdbuspolicy1 public functions while exit
handlers are being called (and thus global objects are being destroyed).

Solution: circumvent destruction of relevant globals altogether.

Change-Id: Ibeab05ed83cc24dc6a5da926fb542f31d8a33af1