Make script fails on go version go1.10 darwin/amd64

[svenpopping]

When running the cmd make on go version go1.10 darwin/amd64the following error occurs:

# github.com/docker/swarmkit/vendor/github.com/google/certificate-transparency/go/x509
vendor/github.com/google/certificate-transparency/go/x509/root_darwin.go:73: cannot use nil as type _Ctype_CFDataRef in assignment
make: *** [bin/swarmd] Error 2

The go version of the google/certificate-transparency dependency has been moved to google/certificate-transparency-go.

The issue with the nil assignment is fixed in google/certificate-transparency-go#155.

[cyli]

This was resolved by #2644