title: bufsize must be an integer error while grepping a message
body: <p>I am running into following error while trying to grep for  a message consisting of multipe lines in a log...can anyone provide inputs on how to overcome this error?</p>
  
  <p>CODE:-</p>
  
  <pre><code>    print gerrit_commitmsg
      gerritlog = Popen('git','log','--grep','gerrit_commitmsg', stdout=PIPE, stderr=PIPE)
      print gerritlog
  </code></pre>
  
  <p>ERROR:-</p>
  
  <pre><code>Commit message:-
  
  Build system changes
  
  Build system changes to include packages in the build
  
  Change-Id: I697558f01ae367d2baacdf2c7fcf1a03753edacd
  
  Traceback (most recent call last):
    File "gerrits_in_workspace.py", line 87, in &lt;module&gt;
      main()
    File "gerrits_in_workspace.py", line 77, in main
      grep_commitmsg(gerrit_commitmsg)
    File "gerrits_in_workspace.py", line 48, in grep_commitmsg
      gerritlog = Popen('git','log','--grep','gerrit_commitmsg', stdout=PIPE, stderr=PIPE)
    File "/usr/lib/python2.7/subprocess.py", line 629, in __init__
      raise TypeError("bufsize must be an integer")
  </code></pre>