stack/nxdtest: Remove default jinja2-template:url

This default prevented extending the section with `inline` option
because `inline` and `url` conflict. This was not a problem when
the deprecated `template` or `template = inline:` option was used.

Setting `url = < nothing >` does not resolve the conflict currently.

Since all section that extend `jinja2-template` set their own `url`
or `inline`, the default value was never used anyway.

The default `filename` option is also no longer needed.

stack/nxdtest.cfg

@@ -37,12 +37,10 @@ extends =
 
 [jinja2-template]
 recipe   = slapos.recipe.template:jinja2
-url = ${:_profile_base_location_}/${:filename}
 output = ${buildout:directory}/${:_buildout_section_name_}
 mode     = 0644
 context  =
   section buildout  buildout
-filename = inline
 
 [nxdtest-instance.cfg]
 <= jinja2-template