Add Midonet plugin support to devstack.

Add support for Midokura's Midonet plugin to devstack,
in lib/neutron_plugins and lib/neutron_thirdparty.

Change-Id: I9b4d90eab09bbb21b9ba251a311620e0a21e8219
Launch ceilometer-alarm-* services.

Add ceilometer-alarm-notify and ceilometer-alarm-eval to the set
of ceilometer services launchable by devstack when explicitly
enabled in the localrc.

Change-Id: I1575437c588cf9079f1e3a6c855123eae09c5dac
Add support for vmdk files as glance images

* Adds support for vmdk files as glance images in upload_image function
* Set default image url to use for vsphere driver in stackrc
* Now using a more stable url

Change-Id: If6d45bc8dfd3c812ded5e1bcf69ad7ebd9b64f34
Merge "Launch ceilometer-alarm-* services."
Fix get_pip_command()

Be more flexible in finding pip, especially after we start replacing it

Change-Id: I14b0ac1584aab99c2fe58a78e3a43196ae8130ca
Merge "Add Midonet plugin support to devstack."
Merge "Add support for vmdk files as glance images"
Merge "Fix get_pip_command()"