Add custom pod conversion functions from pre-v1.1 mirror pods

The functions would default values added after v1.0, so that kubelet wouldn't
fail at comparing the mirror pods against their associated static pods.

This code would need to be maintained if we ever change the default value in
Pod until we drop support for v1.0 nodes.

pkg/api/v1/backward_compatibility_test.go

@@ -153,6 +153,68 @@ func TestCompatibility_v1_PodSecurityContext(t *testing.T) {
 				"spec.hostPID",
 			},
 		},
+		{
+			name: "reseting defaults for pre-v1.1 mirror pods",
+			input: `
+{
+	"kind":"Pod",
+	"apiVersion":"v1",
+	"metadata":{
+		"name":"my-pod-name",
+		"namespace":"my-pod-namespace",
+		"annotations": {
+			"kubernetes.io/config.mirror": "mirror"
+		}
+	},
+	"spec": {
+		"containers":[{
+			"name":"a",
+			"image":"my-container-image",
+			"resources": {
+				"limits": {
+					"cpu": "100m"
+				}
+			}
+		}]
+	}
+}
+`,
+			absentKeys: []string{
+				"spec.terminationGracePeriodSeconds",
+				"spec.containers[0].resources.requests",
+			},
+		},
+		{
+			name: "preserving defaults for v1.1+ mirror pods",
+			input: `
+		{
+			"kind":"Pod",
+			"apiVersion":"v1",
+			"metadata":{
+				"name":"my-pod-name",
+				"namespace":"my-pod-namespace",
+				"annotations": {
+					"kubernetes.io/config.mirror": "cbe924f710c7e26f7693d6a341bcfad0"
+				}
+			},
+			"spec": {
+				"containers":[{
+					"name":"a",
+					"image":"my-container-image",
+					"resources": {
+						"limits": {
+							"cpu": "100m"
+						}
+					}
+				}]
+			}
+		}
+		`,
+			expectedKeys: map[string]string{
+				"spec.terminationGracePeriodSeconds":    "30",
+				"spec.containers[0].resources.requests": "map[cpu:100m]",
+			},
+		},
 	}
 
 	validator := func(obj runtime.Object) fielderrors.ValidationErrorList {