t0021: use $PERL_PATH for rot13-filter.pl

diff --git a/t/t0021/rot13-filter.pl b/t/t0021/rot13-filter.pl
old mode 100755 (executable)
new mode 100644 (file)
index ae4c50f..e3ea58e
--- a/t/t0021/rot13-filter.pl
+++ b/t/t0021/rot13-filter.pl
@@ -1,4 +1,3 @@
-#!/usr/bin/perl
 #
 # Example implementation for the Git filter protocol version 2
 # See Documentation/gitattributes.txt, section "Filter Protocol"