Fixed Jupyter's Unicode file issues by setting the process' locale

@luke @Tyagov 

When SlapOS launches services they don't have their locale set. This was causing problems with unicode characters in Jupyter notebook names. For example, calling the notebook "Ł" crashes Jupyter's kernel. Hardcoding the UTF-8 locale to the ipython_notebook script fixes that but we should look into making a generic fix for any other services that might have this issue in the future.

/reviewed-on nexedi/slapos!193

software/ipython_notebook/instance.cfg.in

@@ -74,9 +74,13 @@ command-line =
 wrapper-path = ${directory:service}/ipython_notebook
 parameters-extra = true
 # Explicitly define IPython Directory to be used while starting ipython notebook
+# Also explicitly force IPython to use en_US.utf8 encoding
 environment =
   IPYTHONDIR=${directory:ipython_dir}
   JUPYTER_CONFIG_DIR=${directory:ipython_dir}
+  LC_ALL=en_US.UTF-8
+  LANG=en_US.UTF-8
+  LANGUAGE=en_US.UTF-8
 
 [ipython-notebook-config]
 <= dynamic-jinja2-template-base

software/ipython_notebook/software.cfg

@@ -64,7 +64,7 @@ recipe = slapos.recipe.template:jinja2
 template = ${:_profile_base_location_}/instance.cfg.in
 rendered = ${buildout:directory}/template.cfg
 mode = 0644
-md5sum = 43cfed9b2dde36265ed48211b42a70dd
+md5sum = 5b7141a56eff4104e6b2c4585ee9448e
 context =
   key bin_directory buildout:bin-directory
   key develop_eggs_directory buildout:develop-eggs-directory