Revert making apply_issue assume 'master'

Review URL: https://codereview.chromium.org/204013002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@257841 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/apply_issue.py b/apply_issue.py
index 3d235ea..690db0d 100755
--- a/apply_issue.py
+++ b/apply_issue.py
@@ -161,13 +161,8 @@
   if scm_type == 'svn':
     scm_obj = checkout.SvnCheckout(full_dir, None, None, None, None)
   elif scm_type == 'git':
-    scm_obj = checkout.GitCheckout(root_dir=full_dir,
-                                   project_name=None,
-                                   remote_branch='master',
-                                   git_url=None,
-                                   commit_user=None,
-                                   base_ref=options.base_ref,
-                                   post_processors=None)
+    scm_obj = checkout.GitCheckout(full_dir, None, None, None, None,
+                                   base_ref=options.base_ref,)
   elif scm_type == None:
     scm_obj = checkout.RawCheckout(full_dir, None, None)
   else:
diff --git a/checkout.py b/checkout.py
index b21f03c..3088757 100644
--- a/checkout.py
+++ b/checkout.py
@@ -562,7 +562,6 @@
     self.git_url = git_url
     self.commit_user = commit_user
     self.remote_branch = remote_branch
-    assert self.remote_branch
     # The working branch where patches will be applied. It will track the
     # remote branch.
     self.working_branch = 'working_branch'
@@ -625,8 +624,7 @@
     # trying again?
     if self.remote_branch:
       self._check_call_git(
-          ['checkout', 
-           '-b', self.working_branch, 
+          ['checkout', '-b', self.working_branch,
            '-t', '%s/%s' % (self.pull_remote, self.remote_branch),
            '--quiet'])