Remove unused params named "context" in filter_attributes
Remove unused params named "context" in filter_attributes

The param named "context" is unused in api/v2/base.py.
Remove these params.

Change-Id: I64295b117a817488185f44ea586b71640fd48a75

eayunstack/neutron,mahak/neutron,mahak/neutron,openstack/neutron,noironetworks/neutron,huntxu/neutron,openstack/neutron,openstack/neutron,eayunstack/neutron,noironetworks/neutron,huntxu/neutron,mahak/neutron