[PATCH 3 of 3] tests: stabilize test-blackbox.t on Windows

[Matt Harbison]

# HG changeset patch
# User Matt Harbison <matt_harbison at yahoo.com>
# Date 1543900773 18000
#      Tue Dec 04 00:19:33 2018 -0500
# Node ID c4beaad9aaf7881d6685cf147f013b95fa62bba7
# Parent  d79558fe55840e43de7eb1b3b05c46b35293d72d
tests: stabilize test-blackbox.t on Windows

I didn't look into why the error is more detailed, but that seems like it's a
good thing (other than for recording tests).

diff --git a/tests/test-blackbox.t b/tests/test-blackbox.t
--- a/tests/test-blackbox.t
+++ b/tests/test-blackbox.t
@@ -347,7 +347,8 @@ Test missing log directory, which should
   > EOF
   $ hg log --debug
   removing $TESTTMP/gone/.hg
-  warning: cannot write to blackbox.log: $ENOENT$
+  warning: cannot write to blackbox.log: $ENOENT$ (no-windows !)
+  warning: cannot write to blackbox.log: $TESTTMP/gone/.hg/blackbox.log: $ENOTDIR$ (windows !)
   $ cd ..
 
 #if chg