objects: remove dict compat support from all XXXList() objects

The XXXList() classes only ever have a single 'objects' attribute
and this is never directly accessed as a dict key, instead all
callers use it in list context. Thus the dict compat support can
be removed from all these objects

Change-Id: I3f8d49d25b99dd0a498dfaad705c6332908cb72f
Merge "objects: remove dict compat support from all XXXList() objects"