nginx: fix uid mapping when building on kremvax

nginx/Dockerfile

@@ -18,7 +18,8 @@ RUN echo "configuring" \
 # forward request and error logs to docker log collector
     && ln -sf /dev/stdout /var/log/nginx/access.log \
     && ln -sf /dev/stderr /var/log/nginx/error.log \
-    && sed -i -e 's/nginx:x:101:102/nginx:x:33:33/' '/etc/passwd' \
+    && sed -i -e 's/nginx:x:[0-9]*:[0-9]*/nginx:x:33:33/' '/etc/passwd' \
+    && grep nginx /etc/passwd \
     && chown -R 33:33 /var/lib/nginx \
     && echo "Done"