[Tile-serving] [osm2pgsql] Fix three format warnings. (#487)

[Landry Breuil]

Your solution also works for me, building git HEAD on OpenBSD doesnt produce warnings anymore on node-ram-cache.cpp

---
Reply to this email directly or view it on GitHub:
https://github.com/openstreetmap/osm2pgsql/pull/487#issuecomment-152479729
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/tile-serving/attachments/20151030/ae3d5051/attachment.html>