[PATCH STABLE] test-hook.t: don't directly use redirect to /dev/null in hook for Windows

[Matt Harbison]

# HG changeset patch
# User Matt Harbison <matt_harbison at yahoo.com>
# Date 1429551790 14400
#      Mon Apr 20 13:43:10 2015 -0400
# Branch stable
# Node ID e8dac25f1ac6e25ecce113d322f28b3e23d00090
# Parent  8678b1eafbcfbd328a48bd24b9e1b5761d06520d
test-hook.t: don't directly use redirect to /dev/null in hook for Windows

This goes with 57f1dbc99631.  External hooks are run in cmd.exe, which doesn't
know about /dev/null, but sh can handle it.

diff --git a/tests/test-hook.t b/tests/test-hook.t
--- a/tests/test-hook.t
+++ b/tests/test-hook.t
@@ -17,7 +17,7 @@ commit hooks can see env vars
   > pretxnclose = sh -c "HG_LOCAL= HG_TAG= python \"$TESTDIR/printenv.py\" pretxnclose"
   > txnclose = sh -c "HG_LOCAL= HG_TAG= python \"$TESTDIR/printenv.py\" txnclose"
   > txnabort = sh -c "HG_LOCAL= HG_TAG= python \"$TESTDIR/printenv.py\" txnabort"
-  > txnclose.checklock = hg debuglock > /dev/null
+  > txnclose.checklock = sh -c "hg debuglock > /dev/null"
   > EOF
   $ echo a > a
   $ hg add a