FIX : Remove bad migration file for this version

htdocs/install/mysql/migration/3.9.0-4.0.0.sql

---
--- Be carefull to requests order.
--- This file must be loaded by calling /install/index.php page
--- when current version is 4.0.0 or higher.
---
--- To rename a table:       ALTER TABLE llx_table RENAME TO llx_table_new;
--- To add a column:         ALTER TABLE llx_table ADD COLUMN newcol varchar(60) NOT NULL DEFAULT '0' AFTER existingcol;
--- To rename a column:      ALTER TABLE llx_table CHANGE COLUMN oldname newname varchar(60);
--- To drop a column:        ALTER TABLE llx_table DROP COLUMN oldname;
--- To change type of field: ALTER TABLE llx_table MODIFY COLUMN name varchar(60);
--- To drop a foreign key:   ALTER TABLE llx_table DROP FOREIGN KEY fk_name;
--- To drop an index:        -- VMYSQL4.0 DROP INDEX nomindex on llx_table
--- To drop an index:        -- VPGSQL8.0 DROP INDEX nomindex
--- To restrict request to Mysql version x.y minimum use -- VMYSQLx.y
--- To restrict request to Pgsql version x.y minimum use -- VPGSQLx.y
--- To make pk to be auto increment (mysql):    VMYSQL4.3 ALTER TABLE llx_c_shipment_mode CHANGE COLUMN rowid rowid INTEGER NOT NULL AUTO_INCREMENT;
--- To make pk to be auto increment (postgres): VPGSQL8.2 NOT POSSIBLE. MUST DELETE/CREATE TABLE
--- To set a field as NULL:                     VPGSQL8.2 ALTER TABLE llx_table ALTER COLUMN name DROP NOT NULL;
--- To set a field as default NULL:             VPGSQL8.2 ALTER TABLE llx_table ALTER COLUMN name SET DEFAULT NULL;
--- Note: fields with type BLOB/TEXT can't have default value.
--- -- VPGSQL8.2 DELETE FROM llx_usergroup_user      WHERE fk_user      NOT IN (SELECT rowid from llx_user);
--- -- VMYSQL4.1 DELETE FROM llx_usergroup_user      WHERE fk_usergroup NOT IN (SELECT rowid from llx_usergroup);
-
-
-ALTER TABLE llx_accounting_bookkeeping ADD COLUMN validated tinyint DEFAULT 0 NOT NULL;