Update bootstrapper.py

[YaoJiayi]

Using vllm serve command cannot activate lmcache. Using entrypoints for now. pypi install works fine but not pip install -e .

Created an issue at #12

[XbzOnGit]

This is likely to be a python import problem.
I met with this problem before, and worked around it by pip install ./ (without -e) every time.
I found that the same module(vllm.worker.model_runner) is imported TWICE when installing with -e, and thus making monkey patching fail.

[qyy2003]

According to my three experiments, it works well. Check if you installed vllm using pip install . -e. That may cause the problem. All my experiments are done using pip install vllm.

Besides, could you activate lmcache_vllm using lmcache_vllm serve in your terminal?