[task scheduler] Move files from build_scheduler/ to task_scheduler/

task_scheduler/go/db/task.go

 package db
 
 import (
         "bytes"
         "encoding/gob"
         "errors"
         "fmt"
         "reflect"
         "sync"
         "time"
@@ skipping 468 matching lines @@
                         glog.Warningf("Duplicate dimension/tag %q.", k)
                 }
         }
 
         tagsList := make([]string, 0, len(tags))
         for k, v := range tags {
                 tagsList = append(tagsList, fmt.Sprintf("%s:%s", k, v))
         }
         return tagsList
 }