Add glog dependency.
Automatic rewrite of relog import paths and calls to use glog.

Commands run:

  find go -name "*.go" | xargs sed --in-place -r 's,"github.com/youtube/vitess/go/relog",log "github.com/golang/glog",g; s,relog.Info,log.Infof,g; s,relog.Warning,log.Warningf,g; s,relog.Error,log.Errorf,g; s,relog.Fatal,log.Fatalf,g; s,relog.Debug,log.V(6).Infof,g'
  find . -name '*.go' -exec gofmt -w {} \;
Convert commands to use glog.

Conflicts:
	go/cmd/vtocc/vtocc.go
	go/cmd/vttablet/vttablet.go
Changes to servenv.Init to reflect new glog API.
Fix tests to work with glog.
Hijack the stdlib logger.
Manually redact password information from logging.
Make /vt/logs default destination for logs.
Glog fixes.