Fix update_port for port = {"port": {"security_groups": []}}

RM10973
Remove distribute from test-requirements.txt

distribute requirement does not work with pip 6.0

RM10986
Merge pull request #297 from asadoughi/rm10973_no_security_groups

Fix update_port for port = {"port": {"security_groups": []}}
Merge pull request #298 from asadoughi/rm10986_distribute_pip6

Remove distribute from test-requirements.txt