[Tile-serving] [osm2pgsql] Fix style.lua error with non numerical layer values (#145)

[apmon]

Merged #145.

---
Reply to this email directly or view it on GitHub:
https://github.com/openstreetmap/osm2pgsql/pull/145#event-118414569
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/tile-serving/attachments/20140506/cb5e6ee9/attachment.html>