[multi-sources-removal] Drop deleted_entities system table and entities.mtime column
since they were only used by the entities_modified_since api of the
repository which has been dropped. Along with them, the multi-sources-etypes
configuration variable and some sql queries at modification/deletion time of
entities. Bon vent !
Related to #2919300
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()