Deletion on the uderlying LDAP server fails

The issue is in fact a consequence of issue #1993092: LDAP *: Why is ldap configuration keyed on user choosen langage ? but created separately for reference purpose.
You should read issue #1993092: LDAP *: Why is ldap configuration keyed on user choosen langage ? first.

When the provisioning in "LDAP Configuration/user/Basic Provisioning to LDAP Settings/LDAP Entry Provisioning Events :Delete LDAP entry when the corresponding Drupal Account is deleted." is set, the deletion does not occur, at least on "non English only site"

The reason is that the provisioning server parameter are stored under a "language" key and the wrong one at user creation time ('und'-efined).
When deleting the account, ldap-module can't find the data and delete the account from the server.

To reproduce:

1. Add a langage to the site and allow it (even leaving english as default)
2. Create a user
3. checks its ldap_user_prov_entries the ldap_user_prov_entries entry wil be with language "und" while the account will have a language of "en".

=> user deletion in the LDAP fails when the account is deleted.