health#provider: fix sys.path for Python

Remove "" from sys.path (typically the first entry), which could cause
e.g. "logging" to be added from the current directory.
This gets done already for loading the host in
runtime/autoload/provider/pythonx.vim.

runtime/autoload/health/provider.vim

@@ -186,7 +186,9 @@ function! s:version_info(python) abort
   endif
 
   let nvim_path = s:trim(s:system([
-        \ a:python, '-c', 'import neovim; print(neovim.__file__)']))
+        \ a:python, '-c',
+        \ 'import sys; sys.path.remove(""); ' .
+        \ 'import neovim; print(neovim.__file__)']))
   if s:shell_error || empty(nvim_path)
     return [python_version, 'unable to load neovim Python module', pypi_version,
           \ nvim_path]