MIT KRB5 Porting

Failing tests

samba3.rpc.samba3.sharesec for plugin_s4_dc

Fails cause of of missing realm's short name canonicalization support source4/auth/kerberos/kerberos_util.c:214 krb5_get_init_creds_opt_set_win2k() Same for samba3.rpc.samba3.sessionkey(plugin_s4_dc), samba3.rpc.samba3.getusername(plugin_s4_dc), samba3.rpc.samr.priv(plugin_s4_dc), samba3.unix.whoami machine account(s3member:local), samba4.rpc.authcontext on ncalrpc with seal,padcheck(dc:local), ...