cubicweb #2408829 ldap: enable some AD configurations to work [validation pending]

the option OPT_REFERRALS needs to be set to 0 for it to work sometimes currently not configurable, only commented code in ldaputils

prioritynormal
typebug
done in3.15.2
load0.500
load left0.000
closed by#2646a8e99b0d [ldap] allow working connection to some ADs (closes #2408829)