Have all test case to use a single base class

* All test cases are able to share on the same config
* All test cases are permitted to use the testresources
	(after we have suitable TestSuite in Tempest)
* On resources name collusion the "resources" variable renamed to
  "os_resources"

Change-Id: I7acf2fac26eefe801a87bcbe4b1caacc762c59b9
Merge "Have all test case to use a single base class"