Fix build-cross

[deads2k]

This mirrors the changes made locally in #13467 .

@jupierce ptal

[deads2k]

[deads@deads-dev-01 origin]$ hack/build-cross.sh 
++ Building go targets for linux/amd64: images/pod cmd/dockerregistry cmd/gitserver pkg/sdn/plugin/sdn-cni-plugin vendor/github.com/containernetworking/cni/plugins/ipam/host-local vendor/github.com/containernetworking/cni/plugins/main/loopback examples/hello-openshift
++ Building go targets for linux/amd64: cmd/openshift cmd/oc
++ Building go targets for darwin/amd64: cmd/openshift cmd/oc
++ Building go targets for windows/amd64: cmd/openshift cmd/oc
++ Building go targets for linux/amd64: test/extended/extended.test
++ Creating openshift-origin-client-tools-v3.6.0-alpha.1-1baf81a-304-linux-64bit.tar.gz
6f82d51c0fe7ce47af44640019a34b1090e8b6b10b849c818935e0525d57e00b  ./kube-scheduler

[jupierce]

lgtm

[deads2k]

[merge]

[openshift-bot]

[Test]ing while waiting on the merge queue

[deads2k]

#12773 re[test]

[openshift-bot]

Evaluated for origin test up to 1baf81a

[openshift-bot]

continuous-integration/openshift-jenkins/test FAILURE (https://ci.openshift.redhat.com/jenkins/job/test_pull_request_origin/1039/) (Base Commit: cd4661d)

[deads2k]

#13942

re[merge]

[openshift-bot]

Evaluated for origin merge up to 1baf81a

[openshift-bot]

continuous-integration/openshift-jenkins/merge SUCCESS (https://ci.openshift.redhat.com/jenkins/job/merge_pull_request_origin/525/) (Base Commit: 4ba7b51) (Image: devenv-rhel7_6191)