remove deprecated code

Author: NicolasCARPi

doc/conf.py

@@ -109,7 +109,6 @@
 # a list of builtin themes.
 #html_theme = 'alabaster'
 html_theme = 'sphinx_rtd_theme'
-html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the