Make release scripts even more robust.

tools/release/releases.py

Index: tools/release/releases.py
diff --git a/tools/release/releases.py b/tools/release/releases.py
index 10bf4d06fb29a75bbfc231d4405f50c425f2f9b1..9ff6e9b8f65b3a00d15a6024daa4990a95c655d1 100755
--- a/tools/release/releases.py
+++ b/tools/release/releases.py
@@ -334,6 +334,7 @@ class UpdateChromiumCheckout(Step):
     cwd = self._options.chromium
     self.GitCheckout("master", cwd=cwd)
     self.GitPull(cwd=cwd)
+    self.DeleteBranch(self.Config("BRANCHNAME"), cwd=cwd)
     self.GitCreateBranch(self.Config("BRANCHNAME"), cwd=cwd)
 
 
@@ -488,6 +489,7 @@ class Releases(ScriptsBase):
     parser.add_argument("--json", help="Path to a JSON file for export.")
 
   def _ProcessOptions(self, options):  # pragma: no cover
+    options.force_readline_defaults = True
     return True
 
   def _Config(self):