[fix] utils/serax.sh create_pyenv() - drop duplicate 'pip install .'

The wrong and unnecessary `pip install .` is executed in /usr/local/searx and is
responsible for the error message:

    ERROR: File "setup.py" not found. Directory cannot be installed in editable mode: /usr/local/searx

The correct pip-install comes right after changing to `cd ${SEARX_SRC}`.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>