Fix a nil pointer access

Signed-off-by: Sascha Schwarze <schwarzs@de.ibm.com>

Author: SaschaSchwarze0

test/e2e/v1alpha1/common_test.go

@@ -255,7 +255,7 @@ func printTestFailureDebugInfo(testBuild *utils.TestBuild, namespace string, bui
 func GetBuildObject(ctx context.Context, client client.Client, buildRun *buildv1alpha1.BuildRun, build *buildv1alpha1.Build) error {
 	// Option #1: BuildRef is specified
 	// An actual Build resource is specified by name and needs to be looked up in the cluster.
-	if buildRun.Spec.BuildRef.Name != "" {
+	if buildRun.Spec.BuildRef != nil && buildRun.Spec.BuildRef.Name != "" {
 		err := client.Get(ctx, types.NamespacedName{Name: buildRun.Spec.BuildName(), Namespace: buildRun.Namespace}, build)
 		if apierrors.IsNotFound(err) {
 			// stop reconciling and mark the BuildRun as Failed