Make sure we do apk upgrade -a

Also base off 3.4 for consistency.

Signed-off-by: Justin Cormack <justin.cormack@docker.com>

alpine/base/alpine-base/Dockerfile

@@ -1,9 +1,9 @@
-FROM alpine:edge
+FROM alpine:3.4
 
 COPY repositories /etc/apk/
 
 RUN \
-  apk update && apk upgrade && \
+  apk update && apk upgrade -a && \
   apk add --no-cache \
   busybox-initscripts \
   chrony \

alpine/base/alpine-base/Makefile

@@ -1,6 +1,6 @@
 .PHONY: tag push
 
-BASE=alpine:edge
+BASE=alpine:3.4
 IMAGE=alpine-base
 
 default: push