[RELEASE-4.7.0] update docker file

Descriptions of the changes in this PR:

update the release version from 4.6.0 to 4.7.0 and its corresponding gpg key

Author: Sijie Guo <sijie@apache.org>

Reviewers: Enrico Olivelli <eolivelli@gmail.com>

This closes apache#1351 from sijie/update_docker_file

docker/Dockerfile

@@ -20,9 +20,9 @@
 FROM centos:7
 MAINTAINER Apache BookKeeper <dev@bookkeeper.apache.org>
 
-ARG BK_VERSION=4.6.0
+ARG BK_VERSION=4.7.0
 ARG DISTRO_NAME=bookkeeper-server-${BK_VERSION}-bin
-ARG GPG_KEY=3ECFCAC4
+ARG GPG_KEY=FD74402C
 
 ENV BOOKIE_PORT=3181
 EXPOSE $BOOKIE_PORT
@@ -36,15 +36,13 @@ RUN set -x \
     && cd /opt \
     && wget -q "https://archive.apache.org/dist/bookkeeper/bookkeeper-${BK_VERSION}/${DISTRO_NAME}.tar.gz" \
     && wget -q "https://archive.apache.org/dist/bookkeeper/bookkeeper-${BK_VERSION}/${DISTRO_NAME}.tar.gz.asc" \
-    && wget -q "https://archive.apache.org/dist/bookkeeper/bookkeeper-${BK_VERSION}/${DISTRO_NAME}.tar.gz.md5" \
     && wget -q "https://archive.apache.org/dist/bookkeeper/bookkeeper-${BK_VERSION}/${DISTRO_NAME}.tar.gz.sha1" \
-    && md5sum -c ${DISTRO_NAME}.tar.gz.md5 \
     && sha1sum -c ${DISTRO_NAME}.tar.gz.sha1 \
     && gpg --keyserver ha.pool.sks-keyservers.net --recv-key "$GPG_KEY" \
     && gpg --batch --verify "$DISTRO_NAME.tar.gz.asc" "$DISTRO_NAME.tar.gz" \
     && tar -xzf "$DISTRO_NAME.tar.gz" \
     && mv bookkeeper-server-${BK_VERSION}/ /opt/bookkeeper/ \
-    && rm -rf "$DISTRO_NAME.tar.gz" "$DISTRO_NAME.tar.gz.asc" "$DISTRO_NAME.tar.gz.md5" "$DISTRO_NAME.tar.gz.sha1" \
+    && rm -rf "$DISTRO_NAME.tar.gz" "$DISTRO_NAME.tar.gz.asc" "$DISTRO_NAME.tar.gz.sha1" \
     && yum remove -y wget \
     && yum clean all