Make release scripts even more robust.

tools/release/common_includes.py

 #!/usr/bin/env python
 # Copyright 2013 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
@@ skipping 493 matching lines @@
   def DieNoManualMode(self, msg=""):
     if not self._options.manual:  # pragma: no cover
       msg = msg or "Only available in manual mode."
       self.Die(msg)
 
   def Confirm(self, msg):
     print "%s [Y/n] " % msg,
     answer = self.ReadLine(default="Y")
     return answer == "" or answer == "Y" or answer == "y"
 
-  def DeleteBranch(self, name):
-    for line in self.GitBranch().splitlines():
+  def DeleteBranch(self, name, cwd=None):
+    for line in self.GitBranch(cwd=cwd).splitlines():
       if re.match(r"\*?\s*%s$" % re.escape(name), line):
         msg = "Branch %s exists, do you want to delete it?" % name
         if self.Confirm(msg):
-          self.GitDeleteBranch(name)
+          self.GitDeleteBranch(name, cwd=cwd)
           print "Branch %s deleted." % name
         else:
           msg = "Can't continue. Please delete branch %s and try again." % name
           self.Die(msg)
 
   def InitialEnvironmentChecks(self, cwd):
     # Cancel if this is not a git checkout.
     if not os.path.exists(os.path.join(cwd, ".git")):  # pragma: no cover
       self.Die("This is not a git checkout, this script won't work for you.")
 
@@ skipping 342 matching lines @@
     for (number, step_class) in enumerate([BootstrapStep] + step_classes):
       steps.append(MakeStep(step_class, number, self._state, self._config,
                             options, self._side_effect_handler))
     for step in steps[options.step:]:
       if step.Run():
         return 0
     return 0
 
   def Run(self, args=None):
     return self.RunSteps(self._Steps(), args)