Commit 29752834fbf3a19e4e117668abfce4e4c7c48ee4 (Add expandable sequences
to krb5_ccachedir) introduce a new behavior that tried to take in account
the fact that parent directories may need to be created as accessible to
anyone by setting them to 01777 permissions.

However the test that determines whether the path shuld be public or not
is flawed and bleeds into pure file templates with undeiserable consequences.

Theis patch corrects thi behavior by clearly returning a specific path if it
need to be made public and preserves any subdir in the template with user
private ownership.

Resolves:
https://fedorahosted.org/sssd/ticket/2071

Consolidate all the code that decides what the ccache name will be
in one function. Conditionalize checking for the old ccache only on
the fact that the new and old name (if any) are actually the same.

Resolves:
https://fedorahosted.org/sssd/ticket/2053

Fix a check for an error return code that can be returned when
the ccache is not found.

Even in case of other errors still do not fail authentication
but allow it to proceed using a new ccache file if necessary.

Related:
https://fedorahosted.org/sssd/ticket/2053

Parameter "int *dp_err" and parameter "int *pam_status" were unused
in static function krb5_auth_prepare_ccache_name.

mem_ctx was unused in function get_domain_or_subdomain