[PATCH 3 of 7 v2] doc: add execute bit and fix shbang line for gendoc.py

[timeless]

# HG changeset patch
# User timeless <timeless at mozdev.org>
# Date 1450771154 0
#      Tue Dec 22 07:59:14 2015 +0000
# Node ID 1d9b7c905bece5a46004f960612be2783af12df1
# Parent  95a008998f65f756bee33d164ec1dc1c3e2e2307
doc: add execute bit and fix shbang line for gendoc.py

diff --git a/doc/gendoc.py b/doc/gendoc.py
old mode 100644
new mode 100755
--- a/doc/gendoc.py
+++ b/doc/gendoc.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 """usage: %s DOC ...
 
 where DOC is the name of a document