Remove unused variable

o cinder/api/openstack/wsgi.py:_CONTENT_TYPE_MAP = {

  This variable was added in the following commit.

    commit c53d8e343e50d4cf7ea9a6a81258848c2d893bfb
    Author: Jenkins <jenkins@review.openstack.org>
    Date:   Thu May 3 10:48:26 2012 -0700

        Initial fork out of Nova.

  But there is no evidence that was used.

Change-Id: I6af64126cf1747ded3369a6237a4cb6cfd250922
Merge "Remove unused variable"