Network objects don't have any method needs to fake.
keys() method is only used by _get_columns() helper
to obtain all attributes of an object. But in compute
network implementation, attributes are obtained from
obj._info directly, which is a dictionary itself. So
there is no need to fake this method.
Change-Id: Ie6a46ef6a3042641e55a7002573ef501db7b60e1
a281ef89a5