fix bug: msg.c_str

lyblsgo

2023-04-11 dc8a0445d5460af16e9926a492a85da592f224bb

 funasr/runtime/python/libtorch/README.md

@@ -31,7 +31,7 @@

    ```shell
    git clone https://github.com/alibaba/FunASR.git && cd FunASR
    cd funasr/runtime/python/funasr_torch
    cd funasr/runtime/python/libtorch
    python setup.py build
    python setup.py install
    ```