Remove a call of `create_symlinks` after the upgrade of existing virtualenv.
Remove a call of `create_symlinks` after the upgrade of existing virtualenv.

The `pyenv-virtualenv` only takes care about the name of executables of `python`,
`setuptools` and `pip`.

pyenv/pyenv-virtualenv,yeonsh/pyenv-virtualenv,yyuu/pyenv-virtualenv,aristiden7o/pyenv-virtualenv,jerr0328/pyenv-virtualenv