Mark depot_tools scripts as bash scripts.

BUG=13668
TEST=none
Review URL: http://codereview.chromium.org/203075

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@26262 0039d316-1c4b-4281-b951-d872f2087c98

drover

-#!/bin/sh
+#!/bin/bash
 # Copyright (c) 2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

gcl

-#!/bin/sh
+#!/bin/bash
 # Copyright (c) 2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

gclient

-#!/bin/sh
+#!/bin/bash
 # Copyright (c) 2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

revert

-#!/bin/sh
+#!/bin/bash
 # Copyright (c) 2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.