fixing two goroutine leaks and one panic

client/v2/client.go

@@ -607,7 +607,9 @@ func (c *simpleHTTPClient) Do(ctx context.Context, act httpAction) (*http.Respon
 
 	select {
 	case <-ctx.Done():
-		resp.Body.Close()
+		if resp != nil {
+			resp.Body.Close()
+		}
 		<-done
 		return nil, nil, ctx.Err()
 	case <-done:

server/storage/mvcc/watchable_store_test.go

@@ -35,6 +35,8 @@ func TestWatch(t *testing.T) {
 	s := newWatchableStore(zap.NewExample(), b, &lease.FakeLessor{}, StoreConfig{})
 
 	defer func() {
+		b.Close()
+		s.Close()
 		s.store.Close()
 		os.Remove(tmpPath)
 	}()
@@ -536,6 +538,8 @@ func TestWatchVictims(t *testing.T) {
 	s := newWatchableStore(zap.NewExample(), b, &lease.FakeLessor{}, StoreConfig{})
 
 	defer func() {
+		b.Close()
+		s.Close()
 		s.store.Close()
 		os.Remove(tmpPath)
 		chanBufLen, maxWatchersPerSync = oldChanBufLen, oldMaxWatchersPerSync