Back out bug 643291 (264508dc959b) on suspicion of causing Tp regressions.

netwerk/streamconv/converters/nsHTTPCompressConv.cpp

@@ -266,8 +266,7 @@ nsHTTPCompressConv::OnDataAvailable(nsIRequest* request,
 
                         // stop an endless loop caused by non-deflate data being labelled as deflate
                         if (mDummyStreamInitialised) {
-                            NS_WARNING("endless loop detected"
-                                       " - invalid deflate");
+                            NS_ERROR("endless loop detected");
                             return NS_ERROR_INVALID_CONTENT_ENCODING;
                         }
                         mDummyStreamInitialised = PR_TRUE;