Jupyter: custom.js isn't a template anymore

@Tyagov  @luke 

/reviewed-on nexedi/slapos!212

software/jupyter/buildout.hash.cfg

@@ -16,7 +16,7 @@
 
 [instance-jupyter-notebook]
 filename = instance.cfg.in
-md5sum = f03d67d3e50a6b5d4572a167dc784bc1
+md5sum = 27bb1bcf71a2f637f539af697ed73445
 
 [jupyter-notebook-config]
 filename = jupyter_notebook_config.py.jinja
@@ -35,5 +35,5 @@ filename = kernel.json.jinja
 md5sum = 33547be93a67530165e079dc3ecfdac3
 
 [custom-js]
-filename = custom.js.jinja
+filename = custom.js
 md5sum = 0bf9e2eb1718b14307265fe05a167018

software/jupyter/instance.cfg.in

@@ -146,8 +146,7 @@ context =
   raw language_name python
 
 [custom-js]
-<= dynamic-jinja2-template-base
-template = {{ custom_js_location }}/{{ custom_js_filename }}
-rendered = ${directory:jupyter_custom_dir}/custom.js
-mode = 0744
+recipe = slapos.cookbook:symbolic.link
+target-directory = ${directory:jupyter_custom_dir}
+link-binary = {{ custom_js_location }}/custom.js