krb5: accept changed principal if krb5_canonicalize=True
Currently SSSD accepts significant changes in the principal only if
krb5_use_enterprise_principal=True. But canonicalization can lead to
similar changes so they should be accepted in this case as well.
Resolves:
https://pagure.io/SSSD/sssd/issue/3408
Reviewed-by: Robbie Harwood <rharwood@redhat.com>
(cherry picked from commit ca95807a9060e454ee68f6f30558d6f7ee968c39)