Fix removing of nodes via CLI without env-id

Removing of nodes from environment using Fuel CLI
fails when 'env-id' parameter isn't specified.
Also it shouldn't try to remove node which isn't
assigned to some environment.

Change-Id: I9e108be401984c2cc42cab63a895c82af9e83610
Closes-bug: #1330412
Merge "Fix removing of nodes via CLI without env-id"