Fix safely-roll-deps.py to use single quotes.

tools/safely-roll-deps.py

 #!/usr/bin/env python
 # Copyright 2014 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.
 
 """Generate a CL to roll a DEPS entry to the specified revision number and post
 it to Rietveld so that the CL will land automatically if it passes the
 commit-queue's checks.
 """
 
@@ skipping 15 matching lines @@
 
 def process_deps(path, project, new_rev, is_dry_run):
   """Update project_revision to |new_issue|.
 
   A bit hacky, could it be made better?
   """
   content = open(path).read()
   # Hack for Blink to get the AutoRollBot running again.
   if project == "blink":
     project = "webkit"
-  old_line = r'(\s+)"%s_revision": "([0-9a-f]{2,40})",' % project
-  new_line = r'\1"%s_revision": "%s",' % (project, new_rev)
+  old_line = r"(\s+)'%s_revision': '([0-9a-f]{2,40})'," % project
+  new_line = r"\1'%s_revision': '%s'," % (project, new_rev)
   new_content = re.sub(old_line, new_line, content, 1)
   old_rev = re.search(old_line, content).group(2)
   if not old_rev or new_content == content:
     die_with_error('Failed to update the DEPS file')
 
   if not is_dry_run:
     open(path, 'w').write(new_content)
   return old_rev
 
 
@@ skipping 104 matching lines @@
     prnt_subprocess.check_call(upload_cmd)
   finally:
     if not options.dry_run:
       prnt_subprocess.check_output(['git', 'checkout', old_branch])
       prnt_subprocess.check_output(['git', 'branch', '-D', new_branch])
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())