Removes extra spaces in get_volume_type.rb.
Removes extra space for list_volume_types.rb.
Refactors create request for delete_volume_test.
Refactors create_request for get_volume_test.
Refactors create_request for get_volume_type_test.
Removes unnecessary variable, adds endpoint test

and refactors create_request.
Uses new way of getting session.