Fix a warning with the new example files

Author: bjori

include/ip-to-country.inc

@@ -98,6 +98,10 @@ function i2c_search_in_index($ip)
     // Read in granularity from index file and
     // convert current IP to something useful
     $granularity = intval(fgets($dbidx, 64));
+    if (!$granularity) {
+        // The file is empty (demo file)
+        return false;
+    }
     $ip_chunk = intval($ip / $granularity);
 
     // Loop till we can read the file