Clean up ML2 Manager

[Lance Bragstad]

Some things need cleanup in the ML2Manager.

1.) In the current ML2 Manager, we are using sys.exit(1) if the network_type isn't found in self.drivers:

https://github.com/openstack/neutron/blob/master/neutron/plugins/ml2/managers.py#L70

Here we should probably throw an exception. When running unit test, if we hit this condition the unit tests will exit as well.

2.) We should also be mindful of using the reserved keyword 'type' and rename type in this case to something else:

https://github.com/openstack/neutron/blob/master/neutron/plugins/ml2/managers.py#L49

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/61351

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/61351
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=ca668a0b9ec5f6412cd842b89d523ba1a8369782
Submitter: Jenkins
Branch: master

commit ca668a0b9ec5f6412cd842b89d523ba1a8369782
Author: zhhuabj <email address hidden>
Date: Thu Jan 16 14:34:14 2014 +0800

    Clean up ML2 Manager

    Some things need cleanup in the ML2Manager.

    1) Replace sys.exit(1) with raise SystemExit(1)
    2) Replace reserved keyword type with network_type

    Change-Id: I921bfaec7d3e31503942b3ca4a1b2218c44b14ac
    Closes-Bug: #1259646