[3919] Removed unused old_leases

src/bin/dhcp6/dhcp6_srv.cc

@@ -1611,7 +1611,6 @@ Dhcpv6Srv::assignIA_PD(const Pkt6Ptr& query, const Pkt6Ptr& answer,
     // will try to honor the hint, but it is just a hint - some other address
     // may be used instead. If fake_allocation is set to false, the lease will
     // be inserted into the LeaseMgr as well.
-    Lease6Collection old_leases;
     AllocEngine::ClientContext6 ctx(subnet, duid, ia->getIAID(), hint, Lease::TYPE_PD,
                                     false, false, string(), fake_allocation);
     ctx.callout_handle_ = getCalloutHandle(query);