Partial victory for Jenkins test on Ec2.

- Need to factor out scope for MachineProvider injection. At present
  it's injected along with JenkinsController. Idea is to run multiple
  Jenkins on single machine instance. At present it's partially implemented
  in MachineProvider.get() to check if a machine is instantiated.
- Jenkins WAR is copied only once via checking in JenkinsProvider.get() method.
  Need to revist it to check for double checked locking issues.