**Describe the issue**
ClickHouse is unable to start up after upgrading from 20.8 to 21.8. 

There is a replicated table with `:` in zk path and it couldn't be loaded with:

`2021.09.15 03:49:58.435071 [ 633075 ] {} <Error> Application: DB::Exception: Unknown auxiliary ZooKeeper name '/test_prefix'. If it's required it can be added to the section <auxiliary_zookeepers> in config.xml: Cannot attach table `db1`.`table1` from metadata file /var/lib/clickhouse/metadata/db1/table1.sql from query ATTACH TABLE db1.table1 (`field1` String, `date` Date) ENGINE = ReplicatedMergeTree('/test_prefix:db1/{shard}/table1', '{replica}') PARTITION BY toMonth(date) PRIMARY KEY field1 ORDER BY field1 SETTINGS index_granularity = 8192: while loading database `db1` from path /var/lib/clickhouse/metadata/db1
`

**Expected behavior**
ClickHouse server is able to startup after upgrade without schema change. "test_prefix" in "/test_prefix:db1/{shard}/table1" is not interpreted as an auxiliary ZooKeeper name.

const String & zookeeper_path, const zkutil::EphemeralNodeHolder::Ptr & metadata_drop_lock, Poco::Logger * logger)
{
    bool completely_removed = false;
    Strings children;
    Coordination::Error code = zookeeper->tryGetChildren(zookeeper_path, children);
    if (code == Coordination::Error::ZNONODE)
        throw Exception(ErrorCodes::LOGICAL_ERROR, "There is a race condition between creation and removal of replicated table. It's a bug");
    for (const auto & child : children)
        if (child != "dropped")
            zookeeper->tryRemoveRecursive(fs::path(zookeeper_path) / child);
    Coordination::Requests ops;
    Coordination::Responses responses;
    ops.emplace_back(zkutil::makeRemoveRequest(metadata_drop_lock->getPath(), -1));
    ops.emplace_back(zkutil::makeRemoveRequest(fs::path(zookeeper_path) / "dropped", -1));
    ops.emplace_back(zkutil::makeRemoveRequest(zookeeper_path, -1));
    code = zookeeper->tryMulti(ops, responses);
    if (code == Coordination::Error::ZNONODE)
    {
        throw Exception(ErrorCodes::LOGICAL_ERROR, "There is a race condition between creation and removal of replicated table. It's a bug");
    }
    else if (code == Coordination::Error::ZNOTEMPTY)
    {
        LOG_ERROR(logger, "Table was not completely removed from ZooKeeper, {} still exists and may contain some garbage,"
                          "but someone is removing it right now.", zookeeper_path);
    }
    else if (code != Coordination::Error::ZOK)
    {
        
        zkutil::KeeperMultiException::check(code, ops, responses);
    }