fix(ldap2rdbm): migration output directory

[devrimyatar]

root@migrate:/install/community-edition-setup# python3 ldap2rdbm.py -rdbm-type="pgsql" -rdbm-user="gluu" -rdbm-password="***" -rdbm-db="gluudb" -rdbm-host="localhost" -rdbm-port="5432"
This is experimental script. Continue anyway? [y/N]y
Please wait while collecting properties...
Dumping data from LDAP Server
Dumping data from LDAP with filter '(objectClass=jansStatEntry)' to /install/community-edition-setup/output/ldap_dump/statistic_data.ldif. This may take a while...
Dumping data from LDAP with filter '(&(objectClass=*)(!(objectClass=jansStatEntry)))' to /install/community-edition-setup/output/ldap_dump/current_data.ldif. This may take a while...
Migrating Statistic Data
Preparing custom schema from attributes
Creating RDBM tables
Traceback (most recent call last):
  File "/install/community-edition-setup/ldap2rdbm.py", line 202, in <module>
    rdbmInstaller.create_tables(schmema_files)
  File "/install/community-edition-setup/setup_app/installers/rdbm.py", line 302, in create_tables
    self.create_table(tbl_name, tables_dict[tbl_name])
  File "/install/community-edition-setup/setup_app/installers/rdbm.py", line 261, in create_table
    self.appendLine(sql_cmd, os.path.join(self.output_dir, 'gluu_tables.sql'), backup=False)
AttributeError: 'RDBMInstaller' object has no attribute 'output_dir'

Use branch https://github.com/GluuFederation/community-edition-setup/tree/ldap-to-pgsql-migration/tools/ldap_to_rdbm