Fixed autodoc can't import/find class error

The right module name should be `novaclient.v1_1.servers' instead of
`novaclient'. Similar fix on `images', `flavors' and `exceptions'.

Removed `ipgroups' and `backup_schedules' since they do not exist any
more.

Closes-Bug: #1056478

Change-Id: Id35f9c275fb36f3651a0bb2b0eb03c43f0aaeec1
remove duplicate six import

apparently we had a duplicate import of six, noticed by pyflakes
in my buffer when loading up the file.

Change-Id: I2f5e03d1862711c7214c1e33b4500693aaabf567