If canon'ing principals, write ccache with updated default principal
* When calling krb5_get_init_creds_keytab() with
krb5_get_init_creds_opt_set_canonicalize() the credential
principal can get updated.
* Create the cache file with the correct default credential.
* LDAP GSSAPI SASL would fail due to the mismatched credentials
before this patch.
https://bugzilla.redhat.com/show_bug.cgi?id=811518