mock_ecc doesn't build

[g2flyer]

Describe the bug

mock_ecc is not yet updated to new signature and modified message formats.

To Reproduce

cd ${FPC_PATH}/integration/test-network
make build GOTAGS="-tags mock_ecc"

Expected behavior
it should build and pass the tests described in README.md.

Log-filesScreenshots

....
go  build -tags mock_ecc -o ecc main.go
# github.com/hyperledger-labs/fabric-private-chaincode/ecc/chaincode/enclave
chaincode/enclave/mock_enclave.go:135:3: unknown field 'RwSet' in struct literal of type protos.ChaincodeResponseMessage
chaincode/enclave/mock_enclave.go:136:3: unknown field 'Signature' in struct literal of type protos.ChaincodeResponseMessage
chaincode/enclave/mock_enclave.go:142:25: assignment mismatch: 3 variables but utils.ReplayReadWrites
returns 1 values
chaincode/enclave/mock_enclave.go:142:65: response.RwSet undefined (type *protos.ChaincodeResponseMessage has no field or method RwSet)
chaincode/enclave/mock_enclave.go:154:10: response.Signature undefined (type *protos.ChaincodeResponseMessage has no field or method Signature)
Makefile:33: recipe for target 'ecc' failed
make[1]: *** [ecc] Error 2
make[1]: Leaving directory '/home/msteiner/src/poet-et-al/go-trusted-chain-code.v2.0/src/github.com/hyperledger-labs/fabric-private-chaincode/ecc'
Makefile:19: recipe for target 'ecc-container' failed
make: *** [ecc-container] Error 2

Environment (please complete the following information):

Independent of environment ...

Additional context

Dependent/related to issue #502

[mbrandenburger]

Fixed with #518