Docker startup: create ${APACHE_LOG_DIR} if it doesn't exist yet

docker/4_run/docker-entrypoint.sh

@@ -19,9 +19,9 @@ if [ ! -f /installed ]; then
 fi
 
 # Make sure that log rotation works.
+mkdir -p ${APACHE_LOG_DIR}
 service cron start
 
-
 if [ "$DEV" = "true" ]; then
     echo "Running in development mode"
     cd /data/git/blender-cloud