Fix file clash in fgetcsv test

Author: nikic

ext/standard/tests/file/bug53848.phpt

@@ -2,7 +2,7 @@
 Bug #53848 (fgetcsv removes leading spaces from fields)
 --FILE--
 <?php
-$file = __DIR__ . "/bug39538.csv";
+$file = __DIR__ . "/bug53848.csv";
 @unlink($file);
 file_put_contents($file, "a,b\n  c,  d");
 $fp = fopen($file, "r");