config: free the file buffer earlier

There is no need to keep config file in memory until the the
configuration is freed. Free the buffer immediately after the
configuration has been parsed.

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>

src/config.c

@@ -200,6 +200,8 @@ int git_config_open(git_config **cfg_out, const char *path)
 	else
 		*cfg_out = cfg;
 
+	gitfo_free_buf(&cfg->reader.buffer);
+
 	return error;
 
  cleanup:
@@ -220,7 +222,6 @@ void git_config_free(git_config *cfg)
 
 	free(cfg->file_path);
 	cvar_list_free(cfg->vars);
-	gitfo_free_buf(&cfg->reader.buffer);
 
 	free(cfg);
 }