rework be_isupdate accordingly to be_isroot

servers/slapd/add.c

servers/slapd/back-bdb/delete.c

servers/slapd/back-bdb/modrdn.c

servers/slapd/back-ldap/add.c

servers/slapd/back-ldap/modify.c

servers/slapd/back-ldbm/delete.c

servers/slapd/back-ldbm/modrdn.c

servers/slapd/backend.c

servers/slapd/delete.c

servers/slapd/modify.c

servers/slapd/modrdn.c

servers/slapd/overlays/ppolicy.c

servers/slapd/overlays/rwm.c

servers/slapd/passwd.c

servers/slapd/proto-slap.h

servers/slapd/slapi/slapi_ops.c

servers/slapd/slapi/slapi_utils.c