Title: #189: SELINUX: Use getseuserbyname to get IPA seuser
@lslebodn I tested the patch in #165 and it successfully resolves the original sssd errors
`[libsemanage] (0x0020): could not query record value` however I don't know if it
would solve the issue reported downstream BZ 1412717, this was the main reason I submitted
I could also modify this PR to not touch **get_seuser()** code and only call
**getseuserbyname()** if **get_seuser()** fails.
See the full comment at https://github.com/SSSD/sssd/pull/189#issuecomment-291228133