native memleak in `ldap-xplat.c` (`ldap_init_thread_func`)

[dafanasiev]

In ldap-xplat.c#L714 you allocate LDAP.

0. before ldap_initialize call just null LDAP*:

data->ld = NULL;

2. ldap_set_option also calls can return other than LDAP_SUCCESS result, so we need to control this (for example):

...
    rc = ldap_set_option(data->ld, LDAP_OPT_REFERRALS, ref_opt);
    if (rc != LDAP_SUCCESS) {
        data->retval = rc;
        goto end;
    }
...

3. and finally at the end label we need to free LDAP struct if we have problems (and allocate it):

end:
// added:
    if(data->retval != LDAP_SUCCESS){
        ldap_destroy(data->ld);
        data->ld = NULL;
    }