[gnome-shell] build: Require bash for pushd

[Philip Chimento <pchimento src gnome org>]

commit 1508d76d32797dc0ba74eee0f80cae48f13e4c97
Author: Philip Chimento <philip chimento gmail com>
Date:   Sat Apr 15 00:00:54 2017 -0700

    build: Require bash for pushd
    
    If using sh, there's no pushd. Make autogen.sh execute with bash instead.

 autogen.sh |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/autogen.sh b/autogen.sh
index 132dc90..560dab8 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 # Run this to generate all the initial makefiles, etc.
 
 srcdir=`dirname $0`