I could not find a reference to NVIM_PYTHON_PYTHON_LOG anywhere, and
python-client looks for NVIM_PYTHON_LOG_FILE.
~/.nvimlog appears to be hardcoded and enabled by default. This would
need to be adjusted when this changes.
Issue: #1537
Running the :UpdateRemotePlugins command will show an ugly, unhelpful
error when no plugins were found. This change has neovim print an error message
and does not attempt to start the python-client which requires at least one
plugin.