e2e/storage: remove unnecessary empty string checks

There is no need to check for empty strings, we can also directly
initialize structs with the value. The end result is the same when the
value is empty (empty string in the struct).

test/e2e/storage/testsuites/provisioning.go

@@ -89,6 +89,7 @@ func createProvisioningTestInput(driver TestDriver, pattern testpatterns.TestPat
 		testCase: StorageClassTest{
 			ClaimSize:    resource.claimSize,
 			ExpectedSize: resource.claimSize,
+			NodeName:     driver.GetDriverInfo().Config.ClientNodeName,
 		},
 		cs:    driver.GetDriverInfo().Config.Framework.ClientSet,
 		dc:    driver.GetDriverInfo().Config.Framework.DynamicClient,
@@ -98,10 +99,6 @@ func createProvisioningTestInput(driver TestDriver, pattern testpatterns.TestPat
 		dInfo: driver.GetDriverInfo(),
 	}
 
-	if driver.GetDriverInfo().Config.ClientNodeName != "" {
-		input.testCase.NodeName = driver.GetDriverInfo().Config.ClientNodeName
-	}
-
 	return resource, input
 }
 
@@ -440,6 +437,7 @@ func runInPodWithVolume(c clientset.Interface, ns, claimName, nodeName, command
 			GenerateName: "pvc-volume-tester-",
 		},
 		Spec: v1.PodSpec{
+			NodeName: nodeName,
 			Containers: []v1.Container{
 				{
 					Name:    "volume-tester",
@@ -470,9 +468,6 @@ func runInPodWithVolume(c clientset.Interface, ns, claimName, nodeName, command
 		},
 	}
 
-	if len(nodeName) != 0 {
-		pod.Spec.NodeName = nodeName
-	}
 	pod, err := c.CoreV1().Pods(ns).Create(pod)
 	framework.ExpectNoError(err, "Failed to create pod: %v", err)
 	defer func() {