Use Go 1.7.4 due to security fixes

build-tools/build-image/cross/Dockerfile

@@ -15,7 +15,7 @@
 # This file creates a standard build environment for building cross
 # platform go binary for the architecture kubernetes cares about.
 
-FROM golang:1.7.3
+FROM golang:1.7.4
 
 ENV GOARM 6
 ENV KUBE_DYNAMIC_CROSSPLATFORMS \
@@ -78,7 +78,7 @@ RUN export ETCD_VERSION=v3.0.14; \
   && ln -s ../src/etcd/etcd-${ETCD_VERSION}-linux-amd64/etcd /usr/local/bin/
 
 # TODO: Remove the patched GOROOT when we have an official golang that has a working arm and ppc64le linker
-ENV K8S_PATCHED_GOLANG_VERSION=1.7.1 \
+ENV K8S_PATCHED_GOLANG_VERSION=1.7.4 \
     K8S_PATCHED_GOROOT=/usr/local/go_k8s_patched
 RUN mkdir -p ${K8S_PATCHED_GOROOT} \
   && curl -sSL https://github.com/golang/go/archive/go${K8S_PATCHED_GOLANG_VERSION}.tar.gz | tar -xz -C ${K8S_PATCHED_GOROOT} --strip-components=1

build-tools/build-image/cross/VERSION

-v1.7.3-1
+v1.7.4-0