Updated openstack/openstack
Project: openstack/neutron  f455d5810ee67d2c9bf07b943ea0463b00d6a001
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Fix bug:range() is not same in py3.x and py2.x

in python3.x, there is no method named xrange(),
it has replaced by range(),which is equal to xrange() in python2.x.
so we must fix this issue.we use six module to fix this issue.

Change-Id: I9cee3f0df2d8abbf6f66d7c5a3a0fed98df622e8
Closes-Bug: #1268439