fix integration tests for alpine3 (#937)

Author: dklimpel

integration-tests/Dockerfile_alpine3

@@ -4,6 +4,7 @@ MAINTAINER Ahmed
 # install apache2 and remove un-needed services
 RUN apk update && \
   apk add --no-cache openrc apache2=2.4.59-r0 bash ca-certificates tinyproxy && \
+  sed -i 's/Listen 80/Listen 0.0.0.0:80/g' /etc/apache2/httpd.conf && \
   rc-update add apache2 && \
   rc-update add tinyproxy && \
   rm -rf /etc/init.d/networking /etc/init.d/hwdrivers /var/cache/apk/* /tmp/*