radius-admin: fix doc on User#find_attribute

(cherry picked from commit e15e87e429c211695d168c35e5585eed0a67df92)
radius-admin: User: *-Password: use Sequel.like

(cherry picked from commit ff6c22c709f5d6e861774f86a0833981b5b3a80d)
radius-admin: User#delete!: referential integrity

Delete termsaccept row(s) BEFORE deleting from other tables.
Merge branch 'master' into margay