Fix HttpProxy: not parse and create HttpProxy from environment variables.

Author: muga

embulk-input-s3/src/main/java/org/embulk/input/s3/AbstractS3FileInputPlugin.java

@@ -92,9 +92,6 @@ public ConfigDiff transaction(ConfigSource config, FileInputPlugin.Control contr
     {
         PluginTask task = config.loadConfig(getTaskClass());
 
-        // configure http proxy
-        task.setHttpProxy(createHttpProxyWithDefault(task));
-
         // list files recursively
         task.setFiles(listFiles(task));
 
@@ -160,14 +157,6 @@ protected ClientConfiguration getClientConfiguration(PluginTask task)
         return clientConfig;
     }
 
-    private Optional<HttpProxy> createHttpProxyWithDefault(PluginTask task)
-    {
-        // If users configure http proxy in in: section, the settings are used. If http proxy settings
-        // don't exist in the config, it searches and extracts from environment variables: "HTTPS_PROXY",
-        // "https_proxy", "HTTP_PROXY", "http_proxy".
-        return task.getHttpProxy().or(HttpProxy.createHttpProxyFromEnv());
-    }
-
     private void setHttpProxyInAwsClient(ClientConfiguration clientConfig, HttpProxy httpProxy)
     {
         // host