We notice that sometimes user build vllm-ascend with incorrect torch
version. In this case, the build is passed, but when running the code,
the error `AttributeError: '_OpNamespace' '_C_ascend' object has no
attribute 'weak_ref_tensor'` is raised. Let's force the torch version to
2.7.1 and check the torch version when build from source to fix the
issue.
closes: #3342
- vLLM version: v0.11.0rc3
- vLLM main:
c9461e05a4
Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>