The 'restart' option of the init script cannot restart CH if it was not able to shutdown in `shutdown_wait_unfinished` seconds.
```
# sudo /etc/init.d/clickhouse-server restart
/var/run/clickhouse-server/clickhouse-server.pid file exists and contains pid = 14388.
The process with pid = 14388 is running.
Sent terminate signal to process with pid 14388.
Waiting for server to stop
/var/run/clickhouse-server/clickhouse-server.pid file exists and contains pid = 14388.
The process with pid = 14388 is running.
Waiting for server to stop
...
/var/run/clickhouse-server/clickhouse-server.pid file exists and contains pid = 14388.
Waiting for server to stop
/var/run/clickhouse-server/clickhouse-server.pid file exists and contains pid = 14388.
Waiting for server to stop
...
/var/run/clickhouse-server/clickhouse-server.pid file exists and contains pid = 14388.
Will terminate forcefully.
Code: 425, e.displayText() = DB::ErrnoException: Cannot send kill signal, errno: 3, strerror: No such process (version 21.1.3.32 (official build))
```
The log:
```
2021.02.08 18:57:23.999226 [ 14388 ] {} <Information> Application: Closed connections. But 3 remain. Tip: To increase wait time add to config: <shutdown_wait_unfinished>60</shutdown_wait_unfinished>
2021.02.08 18:57:24.016684 [ 14388 ] {} <Information> Application: Will shutdown forcefully.
2021.02.08 18:58:28.478835 [ 23658 ] {} <Information> Application: Will watch for the process with pid 23659
2021.02.08 18:58:28.478962 [ 23659 ] {} <Information> Application: Forked a child process to watch
2021.02.08 18:58:28.479067 [ 23659 ] {} <Information> StatusFile: Status file /var/run/clickhouse-server/clickhouse-server.pid already exists - unclean restart. Contents: 14388
2021.02.08 18:58:28.479147 [ 23659 ] {} <Information> SentryWriter: Sending crash reports is disabled
2021.02.08 18:58:28.479183 [ 23659 ] {} <Trace> Pipe: Pipe capacity is 1.00 MiB
2021.02.08 18:58:28.532977 [ 23659 ] {} <Information> : Starting ClickHouse 21.1.3.32 with revision 54445, build id: 63BC1671E8C217170F9B6C6346099FD1F76E784F, PID 23659
2021.02.08 18:58:28.533059 [ 23659 ] {} <Information> Application: starting up
```

fs::path prefix = fs::path(options["prefix"].as<std::string>());
        fs::path bin_dir = prefix / fs::path(options["binary-path"].as<std::string>());
        fs::path main_bin_path = bin_dir / "clickhouse";
        fs::path main_bin_tmp_path = bin_dir / "clickhouse.new";
        fs::path main_bin_old_path = bin_dir / "clickhouse.old";
        size_t binary_size = fs::file_size(binary_self_path);
        bool old_binary_exists = fs::exists(main_bin_path);
        bool already_installed = false;
        
        if (old_binary_exists && binary_self_canonical_path == fs::canonical(main_bin_path))
        {
            already_installed = true;
            fmt::print("ClickHouse binary is already located at {}\n", main_bin_path.string());
        }
        
        else if (old_binary_exists && binary_size == fs::file_size(main_bin_path))
        {
            fmt::print("Found already existing ClickHouse binary at {} having the same size. Will check its contents.\n",
                main_bin_path.string());
            if (filesEqual(binary_self_path.string(), main_bin_path.string()))
            {
                already_installed = true;
                fmt::print("ClickHouse binary is already located at {} and it has the same content as {}\n",
                    main_bin_path.string(), binary_self_canonical_path.string());
            }
        }
        if (already_installed)
        {