Rebalance hung after memcached killed

./testrunner -i /tmp/testexec.24577.ini -p get-cbcollect-info=True,GROUP=bucket_op_with_cron_timers -t eventing.eventing_rebalance.EventingRebalance.test_memcache_crash_on_kv_and_eventing_node_during_eventing_rebalance,doc-per-day=10,dataset=default,nodes_init=5,services_init=kv-kv-eventing-eventing-index:n1ql,groups=simple,reset_services=True,handler_code=bucket_op_with_cron_timers,GROUP=bucket_op_with_cron_timers

function OnUpdate(doc, meta) {

    var expiry = Math.round((new Date()).getTime() / 1000) + 5;

    cronTimer(timerCallback,  expiry, meta.id);

}

function OnDelete(meta) {

    var expiry = Math.round((new Date()).getTime() / 1000) + 5;

    cronTimer(NDtimerCallback,  expiry, meta.id);

}

function NDtimerCallback(docid) {

    delete dst_bucket[docid];

}

function timerCallback(docid) {

    dst_bucket[docid] = 'from timerCallback';

}

function OnUpdate(doc, meta) {

    var doc_id = meta.id;

    log('creating document for : ', doc);

    dst_bucket[doc_id] = {'doc_id' : doc_id}; // SET operation

}

// This is intentionally left blank

function OnDelete(meta) {

    log('deleting document', meta.id);