Remove libs/clock in favor of luci-go/common/clock.

go/src/infra/monitoring/dispatcher/loop_test.go

 package main
 
 import (
         "fmt"
         "testing"
         "time"
 
+        "github.com/luci/luci-go/common/clock"
+        "github.com/luci/luci-go/common/clock/testclock"
         "golang.org/x/net/context"
-        "infra/libs/clock"
-        "infra/libs/clock/testclock"
 )
 
 // Should run f at least once, even if the duration is 0.
 func TestLoopOnce(t *testing.T) {
         _, c := testclock.UseTime(context.Background(), time.Unix(0, 0))
 
         nCalls := 0
         f := func() error {
                 log.Infof("tick")
                 nCalls++
@@ skipping 202 matching lines @@
 
         // Now read off the rest of the timer ticks.
         for i := 0; i < 7; i++ {
                 <-timerStartedC
                 c.Add(1 * time.Second)
         }
 
         c.Add(1 * time.Second)
         <-done
 }