Switch to glog for logging, bridge logging to glog.

1) imported glog to third_party (previous commit)
2) add support for third_party/update.sh to update just one pkg
3) search-and-replace:
  s/log.Printf/glog.Infof/
  s/log.Print/glog.Info/
  s/log.Fatalf/glog.Fatalf/
  s/log.Fatal/glog.Fatal/
4) convert glog.Info.*, err into glog.Error*

Adds some util interfaces to logging and calls them from each cmd, which
will set the default log output to write to glog.  Pass glog-wrapped
Loggers to etcd for logging.

Log files will go to /tmp - we should probably follow this up with a
default log dir for each cmd.

The glog lib is sort of weak in that it only flushes every 30 seconds, so
we spin up our own flushing goroutine.

pkg/registry/endpoints.go

@@ -18,10 +18,10 @@ package registry
 
 import (
 	"fmt"
-	"log"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
+	"github.com/golang/glog"
 )
 
 func MakeEndpointController(serviceRegistry ServiceRegistry, podRegistry PodRegistry) *EndpointController {
@@ -45,7 +45,7 @@ func (e *EndpointController) SyncServiceEndpoints() error {
 	for _, service := range services.Items {
 		pods, err := e.podRegistry.ListPods(labels.Set(service.Selector).AsSelector())
 		if err != nil {
-			log.Printf("Error syncing service: %#v, skipping.", service)
+			glog.Errorf("Error syncing service: %#v, skipping.", service)
 			resultErr = err
 			continue
 		}
@@ -59,7 +59,7 @@ func (e *EndpointController) SyncServiceEndpoints() error {
 			Endpoints: endpoints,
 		})
 		if err != nil {
-			log.Printf("Error updating endpoints: %#v", err)
+			glog.Errorf("Error updating endpoints: %#v", err)
 			continue
 		}
 	}