Move static collection into its own task file.

This also makes it easier to conditionalize it since it
doesn't need to be run on workers.
Add support for worker upstart scripts.
Add a section for the workers to the top level playbook.
Conditionally install workers and start them.
Move worker upstarts to their own files.
Remove endif.
Put the workers on the edxapp machines and into the sandbox.
adding rabbitmq to the sandbox play (needed for workers)
parameterizing edx-workers.conf on service_variants_enabled
Merge pull request #164 from edx/feanil/ansible_workers_rebase

Feanil/ansible workers rebase
Update the ip address to match what ed was previously using for vagrant images.
Looup does not seem to be necessary.

In regular runs it seems to have no side effect but fails for vagrant runs.
Removing migrate_db from group_vars/all.

Putting migratedb in group_vars/all overrides any vars
in playbook files and so migrations never get run.
Update vagrant playbook.

Swap lms and lms-xml nginx ports and remove edxapp_sandbox.yml from vars_files because it no longer exists.
Give the mysql/openid workaround a better name.
Ignore the .vagrant directory.
Merge pull request #167 from edx/feanil/vagrant_updates

Feanil/vagrant updates