fix backends configuration parsing

r2db/db-backends.php

@@ -10,10 +10,11 @@ function noblogs_load_backends($db_config_file, $hashptr) {
     die("Database backends not configured!");
   }
   while (($line = fgets($fp, 1024)) !== false) {
-    if ($line[0] == '#') {
+    $wline = rtrim($line);
+    if ($wline == "" || $wline[0] == '#') {
       continue;
     }
-    $line_parts = explode(" ", rtrim($line));
+    $line_parts = explode(" ", $wline);
     $server_id = $line_parts[0];
     $dataset = "backend_" . $server_id;
     $backend_url = $line_parts[2];