Remove deprecated downloads badge

Author: johnthagen

README.rst

@@ -22,9 +22,6 @@ cpplint JUnit Converter
 .. image:: https://img.shields.io/pypi/pyversions/cpplint-junit.svg
     :target: https://pypi.python.org/pypi/cpplint-junit/
 
-.. image:: https://img.shields.io/pypi/dm/cpplint-junit.svg
-    :target: https://pypi.python.org/pypi/cpplint-junit/
-
 Tool that converts ``cpplint`` output to JUnit XML format.  Use on your CI servers to get more
 helpful feedback.