Range() in for loop need a refactor

[Liang Bo]

In some files, range was called as:
    for i in range(0, 10):
        pass
Actually the start index arg was useless, since its defaultvalue is 0.
They should be refactor as:
    for i in range(10):
        pass

Stats in nova codes, range(N) => 230 lines, range(0, N) => 30 lines

range(N) seems more clear and graceful.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/63133

[Tracy Jones (tjones-i)]

this bug has not been touched in a long time and it's patch(es) are abandoned. Please set back to in progress if you start working on it