remove unnecessary parts, add arm32v5, allow using different dir+image

contrib/docker/release/Dockerfile

@@ -9,16 +9,13 @@ RUN apt-get update && apt-get install -y \
 
 WORKDIR /build
 
-ENV EBUSD_VERSION 21.1
 ENV EBUSD_ARCH amd64
+ENV EBUSD_VERSION 21.1
 
 RUN git clone https://github.com/john30/ebusd.git /build \
     && ./make_all.sh
 
-ARG UPLOAD_URL
-ARG UPLOAD_CREDENTIALS
-ARG UPLOAD_ONLY
-RUN if [ -n "$UPLOAD_URL" ] && [ -n "$UPLOAD_CREDENTIALS" ]; then for img in ebusd-*.deb; do echo "upload $img"; curl -u "$UPLOAD_CREDENTIALS" -s -X POST --data-binary "@$img" -H "Content-Type: application/octet-stream" "$UPLOAD_URL/$img?a=$EBUSD_ARCH&v=$EBUSD_VERSION"; done; if [ -n "$UPLOAD_ONLY" ]; then echo "stopping for upload only"; exit 139; fi fi
+
 
 
 FROM debian:stretch-slim