cubicweb #4268959 Start an instance with a "/" in its name generates bad cookies [open]

I executed by mistake "cubicweb-ctl start brainomics/"
In spite of the slash at the end of the instance it worked
I was able to log in in the web interface and I then got the following error:
Traceback (most recent call last):
  File "/home/yc176684/venv/local/lib/python2.7/site-packages/cubicweb/etwist/", line 128, in render_request
    return self._render_request(request)
  File "/home/yc176684/venv/local/lib/python2.7/site-packages/cubicweb/etwist/", line 153, in _render_request
    content = self.appli.handle_request(req, path)
  File "/home/yc176684/venv/local/lib/python2.7/site-packages/cubicweb/web/", line 350, in main_handle_request
    session = self.get_session(req)
  File "/home/yc176684/venv/local/lib/python2.7/site-packages/cubicweb/web/", line 287, in get_session
    return self.session_handler.get_session(req)
  File "/home/yc176684/venv/local/lib/python2.7/site-packages/cubicweb/web/", line 207, in get_session
    cookie = req.get_cookie()
  File "/home/yc176684/venv/local/lib/python2.7/site-packages/cubicweb/web/", line 568, in get_cookie
    return SimpleCookie(self.get_header('Cookie'))
  File "/usr/lib/python2.7/", line 579, in __init__
    if input: self.load(input)
  File "/usr/lib/python2.7/", line 632, in load
  File "/usr/lib/python2.7/", line 665, in __ParseString
    self.__set(K, rval, cval)
  File "/usr/lib/python2.7/", line 585, in __set
    M.set(key, real_value, coded_value)
  File "/usr/lib/python2.7/", line 460, in set
    raise CookieError("Illegal key value: %s" % key)
CookieError: Illegal key value: __brainomics/_session
The problem is that I was not able to get rid of this error even if I restarted my instance correctly. I had to start another browser or to delete cookies. I think it would be better to raise an error when trying to start "brainomics/".
done in<not specified>
closed by<not specified>