Fix signed/unsigned warning of gcc 3.3.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/branches/1.8@8464 57a11ea4-9604-0410-9ed3-97b8803252fd

src/engine/gnc-commodity.c

@@ -455,7 +455,7 @@ gnc_commodity_table_lookup(const gnc_commodity_table * table,
                            const char * namespace, const char * mnemonic)
 {
   gnc_commodity_namespace * nsp = NULL;
-  int i;
+  unsigned int i;
 
   if (!table || !namespace || !mnemonic) return NULL;