Remove usage of module py3kcompat

Module py3kcompat was removed from oslo-incubator. We need remove its
usage in client side firstly. This make us move smoothly when sync
oslo-incubator code.

Change-Id: I8b07c32c9852e747579a23685f3c8a07ac13ec01
Partial-Bug: #1280033
'name' should as be optional param on aggregate-update

'name' should be an optional parameter not required on aggregate-update,
so we can update 'availability_zone' only.

Change-Id: I23e669a3362e0bea44adc88744eed823ec1e7ebb
Closes-Bug: #1280118
Merge "Remove usage of module py3kcompat"