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/client/client.go

@@ -21,11 +21,11 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"log"
 	"net/http"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
+	"github.com/golang/glog"
 )
 
 // ClientInterface holds the methods for clients of Kubenetes, an interface to allow mock testing
@@ -135,7 +135,7 @@ func (c *Client) rawRequest(method, path string, requestBody io.Reader, target i
 		err = api.DecodeInto(body, target)
 	}
 	if err != nil {
-		log.Printf("Failed to parse: %s\n", string(body))
+		glog.Infof("Failed to parse: %s\n", string(body))
 		// FIXME: no need to return err here?
 	}
 	return body, err