go-compile: Bump to new alpine (with go1.9)
-FROM linuxkit/alpine:ad35b6ddbc70faa07e59a9d7dee7707c08122e8d AS mirror
+FROM linuxkit/alpine:6211ec0252873c9ff9604101fb256353f5a3832a AS mirror
RUN mkdir -p /out/etc/apk && cp -r /etc/apk/* /out/etc/apk/
RUN apk add --no-cache --initdb -p /out \
