Added entity ids to behavior failure messages

* Added server id to timeout failure messages
* Added image id to image timeout failure messages

Change-Id: I0e1805e8dc69a97b07386a3f1ebb137b9615b3b5
Relocated datagen from compute to common package

* Moved the datagen module into the common section of
  CloudCafe to avoid calls into compute code by other
  projects

Change-Id: Ie6ec3d6616cbe5b8cefd2a49ad367f08f620f3cd
Added configurable disk config override

* Added global override for disk config to force
  a specific option for all places where disk config
  is used (create, rebuild, resize)

Change-Id: I19438829f7e3d18470baeea78dcdb8fe367d168a
Merge "Relocated datagen from compute to common package"
Merge "Added entity ids to behavior failure messages"
Merge "Added configurable disk config override"