quickstart: Simplify generated conf.py (language)

sphinx/templates/quickstart/conf.py_t

@@ -61,13 +61,15 @@ source_suffix = {{ suffix | repr }}
 master_doc = {{ master | repr }}
 
 {% endif -%}
+{% if language -%}
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
 #
 # This is also used if you do content translation via gettext catalogs.
 # Usually you set "language" from the command line for these cases.
 language = {{ language | repr }}
 
+{% endif -%}
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
 # This pattern also affects html_static_path and html_extra_path.