fix(proxy): HTTP_PROXY env variable was not removed after os_env_prox…

…y wrapper (#596)

- we restored only if variable defined
- need to remove if no variable defined

qgis_deployment_toolbelt/utils/proxies.py

@@ -190,11 +190,15 @@ def wrapper(*args, **kwargs):
         # Run function
         result = func(*args, **kwargs)
 
-        # Restore environment variable if available
+        # Restore environment variable if available or remove it
         if prev_http_proxy:
             os.environ["HTTP_PROXY"] = prev_http_proxy
+        elif "HTTP_PROXY" in os.environ:
+            del os.environ["HTTP_PROXY"]
         if prev_https_proxy:
             os.environ["HTTPS_PROXY"] = prev_https_proxy
+        elif "HTTPS_PROXY" in os.environ:
+            del os.environ["HTTPS_PROXY"]
         return result
 
     return wrapper