Fix zookeeper import and tests

Import zookeeper.membership rather than zookeeper.membersip.
Also fixed some issues with setting up the tests for the zookeeper
servicegroup driver.  Config options were not being set before
initializing the driver leading to failures.

There is no added test for this because the bug is indistinguishable
from not having the zookeeper python modules installed, which leads to
skipping these servicegroup tests.

Bug 1177776

Change-Id: Idd6dca2e03169399b930cc1fc1a85636497cb0b5
(cherry picked from commit 4a2845095c0e35336c60836050ca11c71898fb8c)
Merge "Fix zookeeper import and tests" into stable/grizzly