Update pre-commit hook to find checkIncludes in its new location

Also add a temporary script to redirect the hook, if people don't
upgrade for a bit.

scripts/git/pre-commit.git-hook

@@ -36,8 +36,8 @@ elif [ -d src/common ]; then
          src/tools/*.[ch]
 fi
 
-if test -e scripts/maint/checkIncludes.py; then
-    python scripts/maint/checkIncludes.py
+if test -e scripts/maint/practracker/includes.py; then
+    python scripts/maint/practracker/includes.py
 fi
 
 if [ -e scripts/maint/practracker/practracker.py ]; then

scripts/maint/checkIncludes.py

@@ -0,0 +1,14 @@
+#!/usr/bin/python
+# Copyright 2018 The Tor Project, Inc.  See LICENSE file for licensing info.
+
+# This file is no longer here; see practracker/includes.py for this
+# functionality.  This is a stub file that exists so that older git
+# hooks will know where to look.
+
+import sys, os
+
+dirname = os.path.split(sys.argv[0])[0]
+new_location = os.path.join(dirname, "practracker", "includes.py")
+python = sys.executable
+
+os.execl(python, python, new_location, *sys.argv[1:])