making string conversions explicit

git-svn-id: svn://10.0.0.236/trunk@67420 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/mailnews/mime/src/mimedrft.cpp

@@ -1338,7 +1338,7 @@ mime_parse_stream_complete (nsMIMESession *stream)
       if (NS_SUCCEEDED(nsMsgI18NConvertToUnicode("UTF-8", body, ucs2)))
         fields->SetBody(ucs2.GetUnicode());
       else
-        fields->SetBody(nsAutoString(body).GetUnicode());
+        fields->SetBody(NS_ConvertASCIItoUCS2(body).GetUnicode());
 
         PR_FREEIF(body);
       } // end if (messageBody)