r/storage_drs_vm_override: Update override test to use automatic SDRS

We changed the default automation level to manual, so fixing this test
so that it has meaning still.

vsphere/resource_vsphere_storage_drs_vm_override_test.go

@@ -407,7 +407,7 @@ resource "vsphere_virtual_machine" "vm" {
 resource "vsphere_storage_drs_vm_override" "drs_vm_override" {
   datastore_cluster_id   = "${vsphere_datastore_cluster.datastore_cluster.id}"
   virtual_machine_id     = "${vsphere_virtual_machine.vm.id}"
-  sdrs_automation_level  = "manual"
+  sdrs_automation_level  = "automated"
   sdrs_intra_vm_affinity = false
 }
 `,