[PATCH STABLE] tests: fix test-patch.t on pickier /bin/sh implementations

[Augie Fackler]

# HG changeset patch
# User Augie Fackler <augie at google.com>
# Date 1526871918 14400
#      Sun May 20 23:05:18 2018 -0400
# Branch stable
# Node ID 0c4019611293212012b598949832dcb2de6b96b2
# Parent  3c84493556db3bffcff2fa2f24bb6738dde9fc58
tests: fix test-patch.t on pickier /bin/sh implementations

This is a graft of 0b39edeff033 and f44306940c94 from default because
I'm tired of seeing the FreeBSD build be red on stable. See those
revisions for details on what's going on here.

diff --git a/tests/test-patch.t b/tests/test-patch.t
--- a/tests/test-patch.t
+++ b/tests/test-patch.t
@@ -92,7 +92,12 @@ Clone and apply patch:
 
 Error exit (issue4746)
 
-  $ hg import ../c/p --config ui.patch='sh -c "exit 1"'
+  $ cat >> exit1.py <<EOF
+  > import sys
+  > sys.exit(1)
+  > EOF
+
+  $ hg import ../c/p --config ui.patch="\"$PYTHON\" \"`pwd`/exit1.py\""
   applying ../c/p
   abort: patch command failed: exited with status 1
   [255]