gradle build stuck and fails at apk upgrade

## Environment details:
Distributed ubuntu14.04 deployment.
# docker --version
Docker version 1.12.0, build 8eab29e

## Steps to reproduce the issue:
gradle build stuck and fails at building "/root/openwhisk/common/scala" as below

---> Running in 3675a25ec163
fetch http://dl-cdn.alpinelinux.org/alpine/v3.6/main/x86_64/APKINDEX.tar.gz

## Additional information you deem important:
While building "common/scala" using Dockerfile, it got stuck at line ==>

RUN apk upgrade --update

Looks like its an issue with alpine image and from within docker container.
However, I am able to wget "http://dl-cdn.alpinelinux.org/alpine/v3.6/main/x86_64/APKINDEX.tar.gz" from an ubuntu14.04 VM.
Do we have any workarounds ?