*: only use docker when releasing, update to Go 1.8, remove aci scripts

This change modifies our release process to only require Docker
when building a release and updates our released binary to use Go
1.8. It also removes our .aci scripts, which we've not been
regularly building.

A nice consequence is that OSX users can now build a release image.

scripts/build-aci

@@ -1,30 +0,0 @@
-#!/usr/bin/env bash
-
-set -e
-
-if [ "$EUID" -ne 0 ]; then
-    echo "This script uses functionality which requires root privileges"
-    exit 1
-fi
-
-# Start the build with an empty ACI
-acbuild --debug begin $1
-
-# In the event of the script exiting, end the build
-trap "{ export EXT=$?; sudo acbuild --debug end && exit $EXT; }" EXIT
-
-# Name the ACI
-acbuild --debug set-name coreos.com/dex
-
-# Add a version label
-acbuild --debug label add version $( ./scripts/git-version )
-
-acbuild --debug run -- apk add --update ca-certificates 
-
-acbuild --debug copy _output/bin/dex /usr/local/bin/dex
-
-acbuild --debug port add www tcp 5556
-acbuild --debug port add grcp tpc 5557
-
-acbuild --debug set-exec -- /usr/local/bin/dex
-acbuild --debug write --overwrite _output/images/dex.aci

scripts/docker-build

@@ -0,0 +1,15 @@
+#!/bin/bash -e
+
+mkdir -p _output/bin
+
+sudo docker run \
+    --cidfile=cid \
+    -v $PWD:/go/src/github.com/coreos/dex:ro \
+    -w /go/src/github.com/coreos/dex \
+    golang:1.8.0-alpine \
+    /bin/sh -x -c \
+    'apk add --no-cache --update alpine-sdk && make release-binary'
+
+sudo docker cp $( cat cid ):/go/bin/dex _output/bin/dex
+sudo docker rm $( cat cid )
+sudo rm cid

scripts/rkt-build

@@ -1,13 +0,0 @@
-#!/bin/bash
-
-mkdir -p _output/bin
-
-sudo rkt run \
-    --volume dex,kind=host,source=$PWD \
-    --mount volume=dex,target=/go/src/github.com/coreos/dex \
-    --dns=8.8.8.8 \
-    --net=host \
-    --insecure-options=image \
-    docker://golang:1.7.4-alpine \
-    --exec=/bin/sh -- -x -c \
-    'apk add --no-cache --update alpine-sdk && cd /go/src/github.com/coreos/dex && make release-binary'