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
```

if (is_symlink && points_to == main_bin_path)
                {
                    need_to_create = false;
                }
                else
                {
                    if (!is_symlink)
                    {
                        fs::path rename_path = symlink_path.replace_extension(".old");
                        fmt::print("File {} already exists but it's not a symlink. Will rename to {}.\n",
                                   symlink_path.string(), rename_path.string());
                        fs::rename(symlink_path, rename_path);
                    }
                    else if (points_to != main_bin_path)
                    {
                        fmt::print("Symlink {} already exists but it points to {}. Will replace the old symlink to {}.\n",
                                   symlink_path.string(), points_to.string(), main_bin_path.string());
                        fs::remove(symlink_path);
                    }
                }
            }
            if (need_to_create)
            {
                fmt::print("Creating symlink {} to {}.\n", symlink_path.string(), main_bin_path.string());
                fs::create_symlink(main_bin_path, symlink_path);
            }
        }
        
        std::string user = options["user"].as<std::string>();
        std::string group = options["group"].as<std::string>();