enable unit test on arm64 platform
Currently, unit test can't be done on arm64 platform
due to multi-arch issue.
Fix points:
golang:1.8.0 doesn't support arm64.
We use golang:1.8 to replace it.
-FROM golang:1.8.0
+FROM golang:1.8
# libseccomp in jessie is not _quite_ new enough -- need backports version
RUN echo 'deb http://httpredir.debian.org/debian jessie-backports main' > /etc/apt/sources.list.d/backports.list
