Fix baremetal stats type

As of 8a7b95dccdbe449d5235868781b30edebd34bacd the resource
tracker code is expecting stats to be a json string.  Baremetal
was setting it to a dict and it was breaking the db write.

Change-Id: I708fecd623c1a42d002c2b20bfdf06b625c9c287
Closes-Bug: #1279572
VMware: fix bug for exceptions thrown in _wait_for_task

If the _call_method fails, for example a resource is not found,
then the same call will be invoked again due to the fact that the
polling task was not stopped.

Closes-Bug: #1246848

Change-Id: If4818e41aed5be03395ab22afc0edf9abb3c34e1
Adds migrate server extension for V3 API

Moves the migrate/live-migrate server functionality out of admin_actions into
its own extension. This part of the blueprint v3-admin-actions-split
allows more selective enablement of features contained in the admin
actions extension.

Note the XML api samples are no longer generated because
bp remove-v3-xml-api has been approved.

Refactor removes some exception handling for migrate along with the relevant tests
as those exceptions will never occur.

Partially implements bp v3-api-admin-actions-split
DocImpact: Adds os-migrate-server extension and moves migrate/live-migrate
functionality out of os-admin-actions into this new extension.

Change-Id: I6b29f501ad6bb9a6401b1c20cd419d9e05fe369b
Merge "Adds migrate server extension for V3 API"
Merge "VMware: fix bug for exceptions thrown in _wait_for_task"
Merge "Fix baremetal stats type"