
If you create configuration file with two disks and specify that disks use the same path, and then create a policy that uses one of these disks then restarting server works and it is possible to create tables, insert and select from them, but on the next restart the server will not start if there are any files on disk.


**How to reproduce**
```xml
<yandex>
    <storage_configuration>
        <disks>
            <default>
                <keep_free_space_bytes>1024</keep_free_space_bytes>
            </default>
            <local1>
                <path>/home/antip/disk1/</path>
            </local1>
            <local2>
                <path>/home/antip/disk1/</path>
            </local2>
        </disks>
        <policies>
            <local1>
                <volumes>
                   <local_volume>
                        <disk>local1</disk>
                   </local_volume>
                </volumes>
            </local1>
        </policies>
    </storage_configuration>
</yandex>
```
```SQL
CREATE TABLE test
(
    ID Int32,
    Value String
)
ENGINE = MergeTree()
PARTITION BY ID
ORDER BY ID
SETTINGS storage_policy = 'local1'
```
```SQL
insert into test values (1, '1111')
```

Now restarting the server will not work.

* 21.10.1.7939 Clickhouse version


**Expected behavior**

Server shall not allow configuration when two or more disks use the same path.

**Errors**
```
ClickHouse client version 21.10.1.7939 (official build).
Connecting to localhost:9000 as user default.
Code: 210. DB::NetException: Connection refused (localhost:9000). (NETWORK_ERROR)
```

**Log**
```
<Error> Application: DB::Exception: Part `1_1_1_0` was found on disk `local2` which is not defined in the storage policy: Cannot attach table `default`.`test` from metadata file /var/lib/clickhouse/store/a1f/a1f83fde-e2be-44d7-a1f8-3fdee2be94d7/test.sql from query ATTACH TABLE default.test UUID 'bce3358a-0c4f-47c3-bce3-358a0c4f67c3' (`ID` Int32, `Value` String) ENGINE = MergeTree PARTITION BY ID ORDER BY ID SETTINGS storage_policy = 'local1', index_granularity = 8192: while loading database `default` from path /var/lib/clickhouse/metadata/default
```


{
    return fs::exists(fs::path(disk_path) / path);
}
bool DiskLocal::isFile(const String & path) const
{
    return fs::is_regular_file(fs::path(disk_path) / path);
}
bool DiskLocal::isDirectory(const String & path) const
{
    return fs::is_directory(fs::path(disk_path) / path);
}
size_t DiskLocal::getFileSize(const String & path) const
{
    return fs::file_size(fs::path(disk_path) / path);
}
void DiskLocal::createDirectory(const String & path)
{
    fs::create_directory(fs::path(disk_path) / path);
}
void DiskLocal::createDirectories(const String & path)
{
    fs::create_directories(fs::path(disk_path) / path);
}
void DiskLocal::clearDirectory(const String & path)