builder-next: disable mergeop and diffop

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
Signed-off-by: Bjorn Neergaard <bneergaard@mirantis.com>
(cherry picked from commit 0ac3bf8)
Signed-off-by: Bjorn Neergaard <bneergaard@mirantis.com>

builder/builder-next/controller.go

@@ -39,6 +39,9 @@ import (
 	"github.com/moby/buildkit/worker"
 	"github.com/pkg/errors"
 	bolt "go.etcd.io/bbolt"
+
+	"github.com/moby/buildkit/solver/pb"
+	"github.com/moby/buildkit/util/apicaps"
 )
 
 func newController(rt http.RoundTripper, opt Opt) (*control.Controller, error) {
@@ -49,6 +52,18 @@ func newController(rt http.RoundTripper, opt Opt) (*control.Controller, error) {
 	dist := opt.Dist
 	root := opt.Root
 
+	pb.Caps.Init(apicaps.Cap{
+		ID:                pb.CapMergeOp,
+		Enabled:           false,
+		DisabledReasonMsg: "only enabled with containerd image store backend",
+	})
+
+	pb.Caps.Init(apicaps.Cap{
+		ID:                pb.CapDiffOp,
+		Enabled:           false,
+		DisabledReasonMsg: "only enabled with containerd image store backend",
+	})
+
 	var driver graphdriver.Driver
 	if ls, ok := dist.LayerStore.(interface {
 		Driver() graphdriver.Driver