(maint) remove intermediate node object from tests

Prior to this commit, spec tests for Nodes controller were failing
because they still had the vestigal remains of the intermediate root
object in json. The actual implementation was changed in b3eac5d. This
commit removes the intermediate root object.
Merge pull request #192 from jeffweiss/remove_intermediate_node_object_from_tests

(maint) remove intermediate node object from tests