[gnumeric] PythonLoader: fix over-eager leak plug.

[Morten Welinder <mortenw src gnome org>]

commit cf8e13ae15365e21b47f146d9b7f439a64190000
Author: Morten Welinder <terra gnome org>
Date:   Sun Mar 21 20:59:00 2021 -0400

    PythonLoader: fix over-eager leak plug.
    
    Unref, use, unref is probably not a good idea.

 plugins/python-loader/gnm-py-interpreter.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)
---
diff --git a/plugins/python-loader/gnm-py-interpreter.c b/plugins/python-loader/gnm-py-interpreter.c
index b0540cf2c..ccc3d9e86 100644
--- a/plugins/python-loader/gnm-py-interpreter.c
+++ b/plugins/python-loader/gnm-py-interpreter.c
@@ -214,12 +214,12 @@ gnm_py_interpreter_run_string (GnmPyInterpreter *interpreter, const char *cmd,
                                                         "stdout");
                g_return_if_fail (saved_stdout_obj != NULL);
                Py_INCREF (saved_stdout_obj);
-               gnm_py_dict_store (sys_module_dict, "stdout",
-                                     stdout_obj);
+               PyDict_SetItemString (sys_module_dict, "stdout", stdout_obj);
+               // We still own a ref to stdout_obj
        }
        if (opt_stderr != NULL) {
                stderr_obj = PyType_GenericNew(interpreter->stringio_class,
-                                           NULL, NULL);
+                                              NULL, NULL);
                if (stderr_obj == NULL)
                        PyErr_Print ();
                g_return_if_fail (stderr_obj != NULL);
@@ -228,16 +228,13 @@ gnm_py_interpreter_run_string (GnmPyInterpreter *interpreter, const char *cmd,
                                                         "stderr");
                g_return_if_fail (saved_stderr_obj != NULL);
                Py_INCREF (saved_stderr_obj);
-               gnm_py_dict_store (sys_module_dict, "stderr",
-                                     stderr_obj);
+               PyDict_SetItemString (sys_module_dict, "stderr", stderr_obj);
+               // We still own a ref to stderr_obj
        }
        run_print_string (cmd, stdout_obj);
        if (opt_stdout != NULL) {
-               gnm_py_dict_store (sys_module_dict, "stdout",
-                                     saved_stdout_obj);
-               Py_DECREF (saved_stdout_obj);
-               py_str = PyObject_CallMethod (stdout_obj, "getvalue",
-                                             NULL);
+               gnm_py_dict_store (sys_module_dict, "stdout", saved_stdout_obj);
+               py_str = PyObject_CallMethod (stdout_obj, "getvalue", NULL);
                if (py_str && PyUnicode_Check (py_str))
                        *opt_stdout = g_strdup (PyUnicode_AsUTF8 (py_str));
                else
@@ -247,11 +244,8 @@ gnm_py_interpreter_run_string (GnmPyInterpreter *interpreter, const char *cmd,
                Py_DECREF (stdout_obj);
        }
        if (opt_stderr != NULL) {
-               gnm_py_dict_store (sys_module_dict, "stderr",
-                                     saved_stderr_obj);
-               Py_DECREF (saved_stderr_obj);
-               py_str = PyObject_CallMethod (stderr_obj, "getvalue",
-                                             NULL);
+               gnm_py_dict_store (sys_module_dict, "stderr", saved_stderr_obj);
+               py_str = PyObject_CallMethod (stderr_obj, "getvalue", NULL);
                if (py_str && PyUnicode_Check (py_str))
                        *opt_stderr = g_strdup (PyUnicode_AsUTF8 (py_str));
                else