(ITS#9076) back-ldap tries to free the wrong controls

[ondra@openldap.org]

Full_Name: Ondrej Kuznik
Version: re24/master
OS: 
URL: 
Submission from: (NULL) (82.132.242.212)


ldap_back_extended_one needs to play with op->o_ctrls since it doesn't just pass
ctrls over like the other sites in back-ldap, but it never sets oldctrls as is
should.

If a control is ever added to the list, it will restore op->o_ctrls to the wrong
value and crash. This happens e.g. in certain chaining scenarios with
mode=legacy.