bisect-kit: fix pylint warnings

depot_tools' pylint was uprev'ed to 1.5.x. This CL fixed warnings from
pylint 1.5.x and 1.8.x.

Also updated pylintrc to match new rules from chromite.

BUG=None
TEST=cros lint *.py bisect_kit/*.py

Change-Id: Iaa134cdfacb03b5b15cd629bd7ff2767ae4e06ef
Reviewed-on: https://chromium-review.googlesource.com/1149945
Commit-Ready: Kuang-che Wu <kcwu@chromium.org>
Tested-by: Kuang-che Wu <kcwu@chromium.org>
Reviewed-by: Chi-Ngai Wan <cnwan@google.com>
diff --git a/bisect_kit/codechange.py b/bisect_kit/codechange.py
index 624437d..a25bf8c 100644
--- a/bisect_kit/codechange.py
+++ b/bisect_kit/codechange.py
@@ -67,11 +67,11 @@
     number and returns (rev, rev, 0).
   """
   m = re.match(_re_intra_rev, rev)
-  if m:
-    return m.group(1), m.group(2), int(m.group(3))
-  else:
+  if not m:
     return rev, rev, 0
 
+  return m.group(1), m.group(2), int(m.group(3))
+
 
 def argtype_intra_rev(argtype):
   """Validates argument is intra-rev.
@@ -269,7 +269,9 @@
                        ], 'unknown action class: %s' % class_name
   for cls in classes:
     if class_name == cls.__name__:
-      return cls(**values)
+      action = cls(**values)
+      break
+  return action
 
 
 class ActionGroup(object):
@@ -361,9 +363,6 @@
 class GitRemoveRepo(Action):
   """Describes a git repo remove action."""
 
-  def __init__(self, timestamp, path):
-    super(GitRemoveRepo, self).__init__(timestamp, path)
-
   def apply(self, root_dir):
     assert self.path
     git_repo = os.path.join(root_dir, self.path)
@@ -501,7 +500,7 @@
     git_root = self.cached_git_root(spec[path].repo_url)
     # spec[path].at is remote reference name. Since git_root is a mirror (not
     # a local checkout), there is no need to convert the name.
-    return git_util.get_rev_by_time(git_root, timestamp, None, spec[path].at)
+    return git_util.get_rev_by_time(git_root, timestamp, branch=spec[path].at)
 
   def get_actions_between_two_commit(self, spec, path, old, new):
     git_root = self.cached_git_root(spec[path].repo_url)