t6000lib: Fix permission

4848509 (Fix permissions on test scripts, 2007-04-13) forgot to make
this included file non-executable.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/t6000lib.sh b/t/t6000lib.sh
old mode 100755
new mode 100644
index d402621..4f72a3d
--- a/t/t6000lib.sh
+++ b/t/t6000lib.sh
@@ -1,3 +1,5 @@
+: included from 6002 and others
+
 [ -d .git/refs/tags ] || mkdir -p .git/refs/tags
 
 :> sed.script