rewrite: fix unit tests, add extra closed check for 2.6 (not sure why its needed now)

pywb/rewrite/rewrite_content.py

@@ -215,7 +215,8 @@ class RewriteContent:
                 buff = first_buff
             else:
                 buff = stream.read()
-                if buff:
+                if buff and (not hasattr(stream, 'closed') or
+                             not stream.closed):
                     buff += stream.readline()
 
             while buff:

pywb/rewrite/test/test_rewrite_live.py

@@ -89,9 +89,6 @@ def test_post():
     env = {'REQUEST_METHOD': 'POST',
            'HTTP_ORIGIN': 'http://httpbin.org',
            'HTTP_HOST': 'httpbin.org',
-           'HTTP_CONNECTION': 'close',
-           'CONTENT_LENGTH': str(len(buff.getvalue())),
-           'CONTENT_TYPE': 'application/x-www-form-urlencoded',
            'wsgi.input': buff}
 
     status_headers, resp_buff = get_rewritten('http://httpbin.org/post', urlrewriter, env=env)