Fix dict.keys() incompatibility in py34 in dhcp test
Fix dict.keys() incompatibility in py34 in dhcp test

os.listdir() returns a list. But in py34, dict.keys()
will no longer return a list, but a iterable. So we
should not assume dict.keys() returns a list in tests.

This problem has not been tested out because we used
assertEqual() to test the result. sorted() will return
a list even if an iterable is passed in. We'd better
not use functions like sorted() to change the type
of the object to be tested.

So in this patch, we use assertItemsEqual() instead to
test if two lists equal to each other, which is not
order sensitive.

Change-Id: I365bcbb35a05c2587953383709254bd2064a69f7
Partial-Bug: #1556379

mahak/neutron,sebrandon1/neutron,MaximNevrov/neutron,mahak/neutron,openstack/neutron,klmitch/neutron,openstack/neutron,cloudbase/neutron,sebrandon1/neutron,huntxu/neutron,noironetworks/neutron,wolverineav/neutron,MaximNevrov/neutron,mahak/neutron,huntxu/neutron,wolverineav/neutron,eayunstack/neutron,igor-toga/local-snat,igor-toga/local-snat,eayunstack/neutron,noironetworks/neutron,klmitch/neutron,cloudbase/neutron,bigswitch/neutron,bigswitch/neutron,openstack/neutron