Make release scripts even more robust.

Also clean up left alone release branch in the chromium
checkout of the v8rel script.

TBR=tandrii@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/1003383003

Cr-Commit-Position: refs/heads/master@{#27197}

tools/release/common_includes.py

@@ -511,12 +511,12 @@ class Step(GitRecipesMixin):
     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

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):

tools/release/test_scripts.py

@@ -1406,6 +1406,10 @@ Cr-Commit-Position: refs/heads/4.2.71@{#1}
       Cmd("git status -s -uno", "", cwd=chrome_dir),
       Cmd("git checkout -f master", "", cwd=chrome_dir),
       Cmd("git pull", "", cwd=chrome_dir),
+      Cmd("git branch", "  branch1\n* %s" % TEST_CONFIG["BRANCHNAME"],
+          cwd=chrome_dir),
+      Cmd("git branch -D %s" % TEST_CONFIG["BRANCHNAME"], "",
+          cwd=chrome_dir),
       Cmd("git new-branch %s" % TEST_CONFIG["BRANCHNAME"], "",
           cwd=chrome_dir),
       Cmd("git fetch origin", "", cwd=chrome_v8_dir),