Move bisect-perf-regression.py into auto_bisect directory.

tools/auto_bisect/source_control.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """This module contains the SourceControl class and related functions."""
 
 import os
 
-from . import bisect_utils
+import bisect_utils
 
 CROS_VERSION_PATTERN = 'new version number from %s'
 
 
 def DetermineAndCreateSourceControl(opts):
   """Attempts to determine the underlying source control workflow and returns
   a SourceControl object.
 
   Returns:
     An instance of a SourceControl object, or None if the current workflow
@@ skipping 265 matching lines @@
         revision_end: End of revision range.
 
     Returns:
         Returns a list of commits that touched this file.
     """
     cmd = ['log', '--format=%H', '%s~1..%s' % (revision_start, revision_end),
            '--', filename]
     output = bisect_utils.CheckRunGit(cmd)
 
     return [o for o in output.split('\n') if o]