Title: #609: SUDO: Don't save duplicates when saving qualified names
The sudoUser attribute which is part of the sudo rule can contain any name
that sudo can parse on the LDAP side. Internally, however, the attribute is
always qualified with the name of the SSSD domain.
This patch makes sure that if two or more sudoUser attributes contain the
same name in both qualified and an unqualified form, the rule is actually
saved. Previously, the rule would have failed to be saved and the sysdb
sudo code would have errored out with EEXIST.
To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/609/head:pr609
git checkout pr609