Fix golint failures in some pkg/kubelet packages

Fixed:
- pkg/kubelet/pod
- pkg/kubelet/metrics
- pkg/kubelet/configmap
- pkg/kubelet/config

pkg/kubelet/configmap/configmap_manager.go

@@ -20,7 +20,7 @@ import (
 	"fmt"
 	"time"
 
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	clientset "k8s.io/client-go/kubernetes"
 	podutil "k8s.io/kubernetes/pkg/api/v1/pod"
 	corev1 "k8s.io/kubernetes/pkg/apis/core/v1"