Fix a couple minor typos in auto_bisect.

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 functions for performing source control operations."""
 
 import bisect_utils
 
 
 def IsInGitRepository():
@@ skipping 107 matching lines @@
 
 def IsInProperBranch():
   """Checks whether the current branch is "master"."""
   cmd = ['rev-parse', '--abbrev-ref', 'HEAD']
   log_output = bisect_utils.CheckRunGit(cmd)
   log_output = log_output.strip()
   return log_output == 'master'
 
 
 def GetCommitPosition(git_revision, cwd=None):
-  """Finds git commit postion for the given git hash.
+  """Finds git commit position for the given git hash.
 
   This function executes "git footer --position-num <git hash>" command to get
   commit position the given revision.
 
   Args:
     git_revision: The git SHA1 to use.
     cwd: Working directory to run the command from.
 
   Returns:
     Git commit position as integer or None.
@@ skipping 85 matching lines @@
       'log',
       '--format=%H',
       '%s~1..%s' % (revision_start, revision_end),
       '--',
       filename,
   ]
   output = bisect_utils.CheckRunGit(cmd)
   lines = output.split('\n')
   return [o for o in lines if o]