Added setup phase, and set environment variables

Also fix a failing test case's assertion
Fix missing paranthesis
Add setup phase
Change username to jenkins
Add quotes
Rename configuration parameters
Rename configuration parameters
Nodepool repo could be specified
Copy ssh keys to root user
Use special xenserver setup, and configure 2 minutes timeout
Increase timeout to avoid:

Traceback (most recent call last):
  File "/home/ubuntu/src/nodepool/nodepool/nodepool.py", line 457, in _run
    self.updateImage(session)
  File "/home/ubuntu/src/nodepool/nodepool/nodepool.py", line 530, in updateImage
    image_id = self.manager.createImage(server_id, hostname)
  File "/home/ubuntu/src/nodepool/nodepool/provider_manager.py", line 361, in createImage
    image_name=image_name))
  File "/home/ubuntu/src/nodepool/nodepool/provider_manager.py", line 251, in submitTask
    return task.wait()
  File "/home/ubuntu/src/nodepool/nodepool/task_manager.py", line 51, in run
    self.done(self.main(client))
  File "/home/ubuntu/src/nodepool/nodepool/provider_manager.py", line 166, in main
    return client.servers.create_image(**self.args)
  File "/usr/local/lib/python2.7/dist-packages/novaclient/v1_1/servers.py", line 773, in create_image
    resp = self._action('createImage', server, body)[0]
  File "/usr/local/lib/python2.7/dist-packages/novaclient/v1_1/servers.py", line 951, in _action
    return self.api.client.post(url, body=body)
  File "/usr/local/lib/python2.7/dist-packages/novaclient/client.py", line 232, in post
    return self._cs_request(url, 'POST', **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/novaclient/client.py", line 213, in _cs_request
    **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/novaclient/client.py", line 195, in _time_request
    resp, body = self.request(url, method, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/novaclient/client.py", line 189, in request
    raise exceptions.from_response(resp, body, url, method)
Conflict: Cannot 'createImage' while instance is in task_state powering-off (HTTP 409) (Request-ID: req-4f4b52a0-5179-465f-8fd5-f81e980a3a0e)
Merge pull request #5 from matelakat/add-setup-phase

Add xenserver support in nodepool