update osm2pgsql to latest master

diff --git a/osm2pgsql b/osm2pgsql
index 759657e11bbf10bbd305102f659ce8288ee04e7d..93b73e5f5c3b20e80027ecf272f553d26f49f2e8 160000 (submodule)
--- a/osm2pgsql
+++ b/osm2pgsql
@@ -1 +1 @@
-Subproject commit 759657e11bbf10bbd305102f659ce8288ee04e7d
+Subproject commit 93b73e5f5c3b20e80027ecf272f553d26f49f2e8