dcerpc.idl: use logical dcerpc_object ordering

dcerpc.idl: use logical dcerpc_object ordering

This IDL code:
typedef [nodiscriminant] union {
	[default] dcerpc_empty empty;
	[case(LIBNDR_FLAG_OBJECT_PRESENT)] GUID object;
} dcerpc_object;

Compiles into the following default-before-case marshalling code:
switch (level) {
	default: {
		NDR_CHECK(ndr_push_dcerpc_empty(ndr, NDR_SCALARS, &r->empty));
	break; }

	case LIBNDR_FLAG_OBJECT_PRESENT: {
		NDR_CHECK(ndr_push_GUID(ndr, NDR_SCALARS, &r->object));
	break; }

}

The default entry before case does not change the flow of execution but
is more logical when present at the end of the switch statement.

Signed-off-by: David Disseldorp <ddiss@samba.org>
Reviewed-by: Guenther Deschner <gd@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>