Remove LDAP osa_princ_ent_rec XDR functions

Remove LDAP osa_princ_ent_rec XDR functions

The LDAP KDB module contained a duplicate set of functions to marshal
osa_princ_ent_ret structures, perhaps to avoid a circular dependency
on libkadm5srv before KDB modules were dynamically loaded.  We have
been using the libkadm5srv versions of those functions from the DB2
KDB module since release 1.8.  Use them from the LDAP KDB module as
well.

Since no rpcgen output remains in princ_xdr.c and princ_xdr.h, add
emacs mode lines for the krb5 C style to those files and make small
formatting adjustments to match.