Instead of overriding the env variables add them to the environment.

Before this change if needed to pass additional env variable to the
ginkgo tester it would remove other variables. With this change it adds
variables specified in the commandline.

pkg/testers/ginkgo/ginkgo.go

@@ -99,7 +99,9 @@ func (t *Tester) Test() error {
 
 	klog.V(0).Infof("Running ginkgo test as %s %+v", t.ginkgoPath, ginkgoArgs)
 	cmd := exec.Command(t.ginkgoPath, ginkgoArgs...)
-	cmd.SetEnv(t.Env...)
+	env := os.Environ()
+	env = append(env, t.Env...)
+	cmd.SetEnv(env...)
 	exec.InheritOutput(cmd)
 	return cmd.Run()
 }