[FIX] Calling read() on a not-existing user id crash instead of returning False
[FIX] name_search() where _rec_name is a reference field and links are broken
[MERGE] [FIX] res_users: skip method _get_reified_groups if read returns no result (avoid traceback)
[MERGE] [FIX] fields: avoid traceback when rendering reference field if link is broken (name_get returns no result)