[FAB-14459] Improve error for key level endorsement

Add a hint about root cause - application capability V1_3 required.

Change-Id: I4c72c4972f31732dff2e6aadd303853d5a1c79e7
Signed-off-by: David Enyeart <enyeart@us.ibm.com>

core/chaincode/handler.go

@@ -572,7 +572,7 @@ func (h *Handler) checkMetadataCap(msg *pb.ChaincodeMessage) error {
 	}
 
 	if !ac.Capabilities().KeyLevelEndorsement() {
-		return errors.New("key level endorsement is not enabled")
+		return errors.New("key level endorsement is not enabled, channel application capability of V1_3 or later is required")
 	}
 	return nil
 }

core/chaincode/handler_test.go

@@ -682,7 +682,7 @@ var _ = Describe("Handler", func() {
 
 			It("returns an error", func() {
 				_, err := handler.HandlePutStateMetadata(incomingMessage, txContext)
-				Expect(err).To(MatchError("key level endorsement is not enabled"))
+				Expect(err).To(MatchError("key level endorsement is not enabled, channel application capability of V1_3 or later is required"))
 			})
 		})
 
@@ -1101,7 +1101,7 @@ var _ = Describe("Handler", func() {
 
 			It("returns an error", func() {
 				_, err := handler.HandleGetStateMetadata(incomingMessage, txContext)
-				Expect(err).To(MatchError("key level endorsement is not enabled"))
+				Expect(err).To(MatchError("key level endorsement is not enabled, channel application capability of V1_3 or later is required"))
 			})
 		})