Fix #891

[kddubey]

Fix #891

As noted in the Python docs, objects can get nullified on interpreter shutdown in __del__. The solution follows the same pattern here

How has this been tested?

1. Install a later version of transformers with torch:

   python -m pip install "transformers[torch]>=4.35.0"
   

2. Checkout main

   git checkout main
   

3. Verify that this command prints out the ignored Exception:

   python -c "import transformers; from llama_cpp import Llama; llm = Llama(model_path='./some.gguf', verbose=False)"
   

4. Checkout this branch

   git checkout ignore-warnings-on-shutdown
   

5. Verify that the same command does not print out the ignored Exception:

   python -c "import transformers; from llama_cpp import Llama; llm = Llama(model_path='./some.gguf', verbose=False)"
   

[kddubey]

@abetlen if this looks good, apply the same changes to your (awesome!) PR here

[abetlen]

This is perfect, thank you!