Update documentation for configuration (#435)

Author: geobeau

README.rst

@@ -223,11 +223,11 @@ for a Flask application:
     blacklist_paths = ['_ah/health']
     middleware = FlaskMiddleware(app, blacklist_paths=blacklist_paths)
 
-For Django, you can configure the blacklist in the ``OPENCENSUS_PARAMS`` in ``settings.py``:
+For Django, you can configure the blacklist in the ``OPENCENSUS_TRACE_PARAMS`` in ``settings.py``:
 
 .. code:: python
 
-    OPENCENSUS_PARAMS: {
+    OPENCENSUS_TRACE_PARAMS: {
         ...
         'BLACKLIST_PATHS': ['_ah/health',],
     }

docs/trace/usage.rst

@@ -166,11 +166,11 @@ for a Flask application:
     blacklist_paths = ['_ah/health']
     middleware = FlaskMiddleware(app, blacklist_paths=blacklist_paths)
 
-For Django, you can configure the blacklist in the ``OPENCENSUS_PARAMS`` in ``settings.py``:
+For Django, you can configure the blacklist in the ``OPENCENSUS_TRACE_PARAMS`` in ``settings.py``:
 
 .. code:: python
 
-    OPENCENSUS_PARAMS: {
+    OPENCENSUS_TRACE_PARAMS: {
         ...
         'BLACKLIST_PATHS': ['_ah/health',],
     }