[views] implement a custom json error view
If the client asked for ``(e)jsonexport`` view, answer
him with a json response rather than an error formatted
in a big HTML blob.
add a custom _requested_vid predicate. In cw 3.21, it will
be deprecated in favor of ``match_form_params(vid=('jsonexport', 'ejsonexport'))``
from logilab.common.shellutils import generate_password
from cubicweb.server.utils import crypt_password
for user in rql('CWUser U WHERE U cw_source S, S name "system", U upassword P, U login L').entities():
salt = user.upassword.getvalue()
if crypt_password('', salt) == salt:
passwd = generate_password()
print 'setting random password for user %s' % user.login
user.set_attributes(upassword=passwd)
commit()