Clean up a couple of compilation errors

common/sched_queue.go

@@ -6,7 +6,6 @@ import (
 	"time"
 
 	"github.com/benbjohnson/clock"
-	"runtime"
 	"sync/atomic"
 )
 

common/sched_queue_test.go

@@ -6,7 +6,6 @@ import (
 
 	"github.com/benbjohnson/clock"
 	wt "github.com/weaveworks/weave/testing"
-	"log"
 )
 
 // Ensure we can add new calls while forwarding the clock