fix: image URL for python version

Author: satra

doc/_templates/indexsidebar.html

@@ -7,7 +7,7 @@ <h3>{{ _('Links') }}</h3>
     <li>Forum: <a href="http://groups.google.com/group/nipy-user">User</a> · <a href="http://projects.scipy.org/mailman/listinfo/nipy-devel">Developer</a></li>
     <li><a href="http://nipy.org/software/license/index.html"><img src="https://pypip.in/license/nipype/badge.png" alt="License"></a> · <a href="http://nipy.org/about/funding.html">Funding</a></li>
     <li><a href="https://travis-ci.org/nipy/nipype"><img src="https://travis-ci.org/nipy/nipype.png?branch=master" alt="travis"></a> · <a href='https://coveralls.io/r/nipy/nipype'><img src='https://coveralls.io/repos/nipy/nipype/badge.png' alt='Coverage Status' /></a></li>
-    <li><a href="https://pypi.python.org/pypi/nipype/"><img src="https://pypip.in/download/nipype/badge.png" alt="Downloads"></a> · <a href='https://pypi.python.org/pypi/nipype/'><img src='https://pypip.in/py_versions/nipype/badge.pngg' alt='Python Versions' /></a></li>
+    <li><a href="https://pypi.python.org/pypi/nipype/"><img src="https://pypip.in/download/nipype/badge.png" alt="Downloads"></a> · <a href='https://pypi.python.org/pypi/nipype/'><img src='https://pypip.in/py_versions/nipype/badge.png' alt='Python Versions' /></a></li>
 </ul>
 
 {% endblock %}