fix some bugs in linux

toolbox.py

@@ -783,8 +783,9 @@ class ProxyNetworkActivate():
         from toolbox import get_conf
         proxies, = get_conf('proxies')
         if 'no_proxy' in os.environ: os.environ.pop('no_proxy')
-        os.environ['HTTP_PROXY'] = proxies['http']
-        os.environ['HTTPS_PROXY'] = proxies['https']
+        if proxies is not None:
+            if 'http' in proxies: os.environ['HTTP_PROXY'] = proxies['http']
+            if 'https' in proxies: os.environ['HTTPS_PROXY'] = proxies['https']
         return self
 
     def __exit__(self, exc_type, exc_value, traceback):