[CT+DM] Change location of SKPs dir to outside checkouts

chrome/ct_dm.isolate

 # Copyright (c) 2015 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.
 
 {
   'conditions': [
     ['OS=="linux"', {
       'variables': {
         'files': [
           '../../skia/resources/',
           '../../skia/out/Debug/dm',
           '../content/test/ct/run_ct_dm.py',
-          '../content/test/ct/slave<(SLAVE_NUM)/skps/',
+          '../../skps/slave<(SLAVE_NUM)/',
         ],
         'command': [
           'python',
           '../content/test/ct/run_ct_dm.py',
           '--slave_num=<(SLAVE_NUM)',
         ],
       },
     }],
   ]
 }