LU-6020 kerberos: checksum errors when using kerberos

LU-6020 kerberos: checksum errors when using kerberos

derive_key_lucid() uses krb5int_derive_key() to
construct the requested key. However, in the
end it copies the key from kout keyblock, whereas
the derive function puts it into key_out. The
original code contains the invalid assumption
that krb5_k_create_key() binds the newly created
key to the keyblock which was used to create it.

Xyratex-bug-id: SNT-15
Signed-off-by: Andrew Perepechko <andrew.perepechko@seagate.com>
Change-Id: Id2f28b4a9ca3909861a703f2ce07ed860087e809
Reviewed-on: http://review.whamcloud.com/13076
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>