Revive conformance test.

Use KUBE_CONFIG_FILE instead of AUTH_CONFIG (and CERT_DIR).

Pass GINKGO_TEST_ARGS for a subset of e2e tests which
@erictune has deemed initially sufficient for conformance.

Allow GINKGO_TEST_ARGS to pass through hack/ginkgo-e2e.sh.

Set NUM_MINIONS (need better way to handle this).

Remove use of "KUBERNETES_CONFORMANCE_TEST" variable
and use of KUBERNETES_PROVIDER="conformance_test" convention,
both of which have no apparent purpose.

Allow unset testContext.provider in test/e2e/e2e_test.go
Allow testContext.Provider to be unset in providerIs().

test/e2e/e2e_test.go

@@ -103,9 +103,8 @@ func TestE2E(t *testing.T) {
 	util.InitLogs()
 	defer util.FlushLogs()
 
-	// TODO: possibly clean up or refactor this functionality.
 	if testContext.Provider == "" {
-		glog.Fatal("The --provider flag is not set.  Treating as a conformance test.  Some tests may not be run.")
+		glog.Info("The --provider flag is not set.  Treating as a conformance test.  Some tests may not be run.")
 	}
 
 	if testContext.Provider == "aws" {