[PATCH] test-ssh: stabilize for Windows

[Matt Harbison]

# HG changeset patch
# User Matt Harbison <matt_harbison at yahoo.com>
# Date 1513468682 18000
#      Sat Dec 16 18:58:02 2017 -0500
# Node ID f67a73a92906327b6c0a85e477e4fad48b3869b8
# Parent  01b084914a60ec8d1e0f85c8bb4ee96fc38d8404
test-ssh: stabilize for Windows

Previously, this complained:

    remote: '.' is not recognized as an internal or external command,
    remote: operable program or batch file.

Making this a python script apparently revealed some races[1].  Thanks to Yuya
for suggesting this.

[1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-December/109094.html

diff --git a/tests/test-ssh.t b/tests/test-ssh.t
--- a/tests/test-ssh.t
+++ b/tests/test-ssh.t
@@ -603,12 +603,12 @@
   > echo \$VAR >&2
   > EOF
   $ chmod +x dumpenv
-  $ hg pull ssh://something --config ui.ssh="./dumpenv"
+  $ hg pull ssh://something --config ui.ssh="sh dumpenv"
   pulling from ssh://something/
   remote: 
   abort: no suitable response from remote hg!
   [255]
-  $ hg pull ssh://something --config ui.ssh="./dumpenv" --config sshenv.VAR=17
+  $ hg pull ssh://something --config ui.ssh="sh dumpenv" --config sshenv.VAR=17
   pulling from ssh://something/
   remote: 17
   abort: no suitable response from remote hg!