v1beta1 should return Minion as kind, rather than Node

This changes the internal name logic (for conversion) to prefer the
internal registered preferred name for a resource, and then makes
v1beta1 and v1beta2 prefer Minion.

Fixes #3010
Merge pull request #3014 from smarterclayton/fix_name_of_minion_in_v1beta1

v1beta1 should return Minion as kind, rather than Node