Remove a useless arg in range()

Modify tests/test_v3_auth.py, remove the useless arg ("start index" = 0)
since its default value is 0. There was no range(0, N) being called in
any other place except here in keystone sources.

Change-Id: Ifce3384982476a7b9884a51aa73fdb45798e3051
Merge "Remove a useless arg in range()"