Removing the %erp5_url magic

@luke @Tyagov 

In Jupyter notebooks users could enter the url of their `Base_executeJupyter` function, but [it now gets filled in automatically](https://lab.nexedi.com/nexedi/slapos/blob/2f2a5ad0/software/ipython_notebook/template/ERP5kernel.py.jinja#L10). This makes the `%erp5_url` magic redundant which is why we can remove it. This commit also removes all mentions of `%erp5_url` in the kernel output and `custom.js`.

/reviewed-on nexedi/slapos!185

software/ipython_notebook/software.cfg

@@ -47,7 +47,7 @@ md5sum = d7d4a7e19d55bf14007819258bf42100
 [erp5-kernel]
 <= download-file-base
 filename = ERP5kernel.py.jinja
-md5sum = b5bb94181f7faee42ad18a909a648fe5
+md5sum = f7be6c3ef9cdfaaea3b8756895a22081
 
 [kernel-json]
 <= download-file-base
@@ -57,7 +57,7 @@ md5sum = ab6e78ea20855e07d388b5b86d1770fe
 [custom-js]
 <= download-file-base
 filename = custom.js.jinja
-md5sum = 13561a9d86c488be752795e7bc23474a
+md5sum = 584aa839aa20263ba885537b74c83abd
 
 [instance-jupyter]
 recipe = slapos.recipe.template:jinja2

software/ipython_notebook/template/ERP5kernel.py.jinja

@@ -184,12 +184,8 @@ notebooks. \n' % magic_value
     if check_attributes:
       self.response = 'You have entered all required magics. You may now use your notebook.'
     else:
-      self.response = '''You have these required magics remaining: %s. \nYour current \
-backend url is %s (you can change it with %serp5_url)''' % (
-      ', '.join(map(str, missing_attributes)), 
-      str(self.url),
-      '%'
-      )
+      self.response = '''You have these required magics remaining: %s. \n''' % (
+      ', '.join(map(str, missing_attributes)))
 
     # Display response to frontend before moving forward
     self.display_response(response=(self.response + '\n'))

software/ipython_notebook/template/custom.js.jinja

@@ -85,12 +85,11 @@ $([IPython.events]).on('notebook_loaded.Notebook', function(){
   var kernelname = IPython.notebook.kernel_selector.current_selection;
   var display_text="<div class='output_subarea output_text output_result'>\
   <pre>Follow these steps to customize your notebook with ERP5 kernel :-</br>\
-  1. Add <b>%erp5_url &lt;your_erp5_url&gt;/erp5/Base_executeJupyter</b>.</br>\
-  Make sure you have 'erp5_data_notebook' business template installed in your ERP5</br>\
-  2. <b>%notebook_set_reference &lt;your_notebook_refernce&gt;</b></br>\
+  1. Make sure you have 'erp5_data_notebook' business template installed in your ERP5</br>\
+  2. <b>%erp5_user &lt;your_erp5_username&gt;</b></br>\
+  3. <b>%erp5_password &lt;your_erp5_password&gt;</b></br>\
+  4. <b>%notebook_set_reference &lt;your_notebook_reference&gt;</b></br>\
   It would be better to set the reference to match with erp5 reference pattern.</br>\
-  3. <b>%erp5_user &lt;your_erp5_username&gt;</b></br>\
-  4. <b>%erp5_password &lt;your_erp5_password&gt;</b></br>\
   5. As soon as you see 'Please Proceed' message you can now access your erp5 using notebook.</br>\
   <p><u>OTHER USEFUL MAGICS</u> -</br>\
   <b>%my_notebooks</b> -This is used to display all the notebooks created by the specific user.</br>\