[#204] gc: Fix GC handlers start

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/local_object_storage/shard/gc.go

@@ -136,7 +136,8 @@ func (gc *gc) listenEvents(ctx context.Context) {
 		v.cancelFunc()
 		v.prevGroup.Wait()
 
-		ctx, v.cancelFunc = context.WithCancel(ctx)
+		var runCtx context.Context
+		runCtx, v.cancelFunc = context.WithCancel(ctx)
 
 		v.prevGroup.Add(len(v.handlers))
 
@@ -144,7 +145,7 @@ func (gc *gc) listenEvents(ctx context.Context) {
 			h := v.handlers[i]
 
 			err := gc.workerPool.Submit(func() {
-				h(ctx, event)
+				h(runCtx, event)
 				v.prevGroup.Done()
 			})
 			if err != nil {