Make use of suppress_stdout_stderr when freeing model

[paschembri]

Fixes #802

[BlueBlazin]

When I made this change manually on my local llama.py I get the following error:

NameError: name 'open' is not defined

llama_cpp version: 0.2.11
python version: 3.11.0
OS: MacOS Sonoma

Is it just an issue for me or everyone? It's a well known issue that's supposedly fixed in 3.9*:
https://bugs.python.org/issue26789

I can easily resolve this by adding a del model at the end of my code to trigger model deletion before CPython starts shutting down but this is not ideal. Any suggestions?

* Never mind, that fix is for the logging module.