Jupyter: --matplotlib=inline is nether supported nor needed

@jerome added --matplotlib=inline in 48eefab5 (ipython notebook) but it is
really neither needed:

   @jerome
   I remember adding this --matplotlib=inline line, but I am not sure it was
   ever needed. Using magic %matplotlib in notebook should be enough.

   @tiwariayush
   Yeah, for inline matplotlib in default python kernel, magics do there
   work(therefore neither pylab nor matplotlib alias are needed while starting the
   server), so I'd say leave this commit as it is and regarding version updation:
   a new patch making change wherever required.

nor supported:

   $ cat .slappart0_ipython_notebook.log
   [W 15:51:35.454 NotebookApp] Unrecognized alias: '--matplotlib=inline', it will probably have no effect.

Remove it.

P.S.

'--logfile' isn't available for ipython version 3.2.0 but we are not removing
it since we are planning to upgrade IPython to versions 4.x where it is supported.

Based on patch by @tiwariayush  (see nexedi/slapos!33)

software/ipython_notebook/instance.cfg.in

@@ -73,7 +73,6 @@ recipe = slapos.cookbook:wrapper
 command-line =
   {{ bin_directory }}/ipython notebook
   --no-browser
-  --matplotlib=inline
   --ip=${instance-parameter:host}
   --port=${instance-parameter:port}
   --port-retries=0

software/ipython_notebook/software.cfg

@@ -60,7 +60,7 @@ recipe = slapos.recipe.template:jinja2
 template = ${:_profile_base_location_}/instance.cfg.in
 rendered = ${buildout:directory}/template.cfg
 mode = 0644
-md5sum = 53d0a2f8bad24b81ee3953fec431b16f
+md5sum = 1a993b1f8fa3f001c45075fe95a48332
 context =
   key bin_directory buildout:bin-directory
   key develop_eggs_directory buildout:develop-eggs-directory