NXD clone_panel: Remove SSH option completely

The default was switched to HTTP in the previous patch, but let's completely
remove SSH option - we support only HTTP for git fetch/push.

app/views/shared/_clone_panel.html.haml

 - project = project || @project
 
 .git-clone-holder.input-group
-  .input-group-btn
+  -# no ssh clone - only http is supported
+  -# .input-group-btn
     %a#clone-dropdown.clone-dropdown-btn.btn{href: '#', 'data-toggle' => 'dropdown'}
       %span
         = default_clone_protocol.upcase