Run entrypoint though sh instead of dumb-init with Alpine

Dockerfile.alpine

@@ -6,7 +6,7 @@ VOLUME /config
 
 ENV DOCKERIZE_VERSION=v0.6.0
 RUN echo "@testing http://dl-cdn.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories \
-    && apk --no-cache add dumb-init ip6tables ufw@testing openvpn shadow transmission-daemon \
+    && apk --no-cache add ip6tables ufw@testing openvpn shadow transmission-daemon \
     && echo "Install dockerize $DOCKERIZE_VERSION" \
     && wget -qO- https://github.com/jwilder/dockerize/releases/download/$DOCKERIZE_VERSION/dockerize-linux-amd64-$DOCKERIZE_VERSION.tar.gz | tar xz -C /usr/bin \
     && mkdir -p /opt/transmission-ui/combustion-release /opt/transmission-ui/kettu \
@@ -108,4 +108,4 @@ ENV OPENVPN_USERNAME=**None** \
 
 # Expose port and run
 EXPOSE 9091
-CMD ["dumb-init", "/etc/openvpn/start.sh"]
+CMD ["sh", "/etc/openvpn/start.sh"]