The only thing preventing this from happening earlier was the circular sysfs
registration dependency - it would need to be initialized before it was 
registered, but needed to be registered before it was initialized. 

With kobjects gone from struct filesystem_type, the dependency no longer 
exists and we don't have to special-case the possibility that a kobject will
be passed to kobject_get with a refcount == 0. 

Note that a kobject with a count of 0 in that function is still a bug, but 
one in the subsystem making the call. We should add a debugging hook to dump
the stack if it does happen.