title: strptime -- Invalid Date Error
body: <p>This should be super simple, but I am stumped:</p>
  
  <pre class="lang-rb prettyprint-override"><code>require 'time'
  # works fine, prints "2/20/2012 6:46:00 PM"
  puts Time.new(2012,2,20,18,46,0).strftime('%-m/%-d/%Y %-l:%M:%S %p')
  test_date = '2/20/2012 6:46:00 PM'
  # Invalid date error -- why??
  # What am I doing wrong in my usage of strptime?
  last_login = DateTime.strptime(test_date, '%-m/%-d/%Y %-l:%M:%S %p')
  </code></pre>
  
  <p>Thanks!</p>