go/zodb/zeo: Don't avoid defer

Starting from Go1.14 defer is no longer slow:
https://golang.org/doc/go1.14#runtime

go/zodb/storage/zeo/zeo.go

@@ -73,16 +73,13 @@ func (z *zeo) Sync(ctx context.Context) (head zodb.Tid, err error) {
 	return head, nil
 }
 
-func (z *zeo) Load(ctx context.Context, xid zodb.Xid) (*mem.Buf, zodb.Tid, error) {
-	// defer func() ...
-	buf, serial, err := z._Load(ctx, xid)
+func (z *zeo) Load(ctx context.Context, xid zodb.Xid) (buf *mem.Buf, serial zodb.Tid, err error) {
+	defer func() {
 		if err != nil {
 			err = &zodb.OpError{URL: z.URL(), Op: "load", Args: xid, Err: err}
 		}
-	return buf, serial, err
-}
+	}()
 
-func (z *zeo) _Load(ctx context.Context, xid zodb.Xid) (*mem.Buf, zodb.Tid, error) {
 	rpc := z.rpc("loadBefore")
 	xres, err := rpc.call(ctx, oidPack(xid.Oid), tidPack(xid.At+1)) // XXX at2Before
 	if err != nil {

go/zodb/storage/zeo/zrpc.go

@@ -216,16 +216,13 @@ func pktDecode(pkb *pktBuf) (msg, error) {
 
 
 // Call makes 1 RPC call to server, waits for reply and returns it.
-func (zl *zLink) Call(ctx context.Context, method string, argv ...interface{}) (reply msg, _ error) {
-	// defer func() ...
-	reply, err := zl._call(ctx, method, argv...)
+func (zl *zLink) Call(ctx context.Context, method string, argv ...interface{}) (reply msg, err error) {
+	defer func() {
 		if err != nil {
 			err = fmt.Errorf("%s: call %s: %s", zl.link.RemoteAddr(), method, err)
 		}
-	return reply, err
-}
+	}()
 
-func (zl *zLink) _call(ctx context.Context, method string, argv ...interface{}) (reply msg, _ error) {
 	rxc := make(chan msg, 1) // reply will go here
 
 	// register our call
@@ -242,7 +239,7 @@ func (zl *zLink) _call(ctx context.Context, method string, argv ...interface{})
 	// (msgid, async, method, argv)
 	pkb := allocPkb()
 	p := pickle.NewEncoder(pkb)
-	err := p.Encode(pickle.Tuple{callID, false, method, pickle.Tuple(argv)})
+	err = p.Encode(pickle.Tuple{callID, false, method, pickle.Tuple(argv)})
 	if err != nil {
 		panic(err) // all our types are expected to be supported by pickle
 	}