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 (0 != chmod(main_bin_path.string().c_str(), S_IRUSR | S_IRGRP | S_IROTH | S_IXUSR | S_IXGRP | S_IXOTH))
                throwFromErrno(fmt::format("Cannot chmod {}", main_bin_path.string()), ErrorCodes::SYSTEM_ERROR);
        }
        else
        {
            size_t available_space = fs::space(bin_dir).available;
            if (available_space < binary_size)
                throw Exception(ErrorCodes::NOT_ENOUGH_SPACE, "Not enough space for clickhouse binary in {}, required {}, available {}.",
                    bin_dir.string(), ReadableSize(binary_size), ReadableSize(available_space));
            fmt::print("Copying ClickHouse binary to {}\n", main_bin_tmp_path.string());
            try
            {
                ReadBufferFromFile in(binary_self_path.string());
                WriteBufferFromFile out(main_bin_tmp_path.string());
                copyData(in, out);
                out.sync();
                if (0 != fchmod(out.getFD(), S_IRUSR | S_IRGRP | S_IROTH | S_IXUSR | S_IXGRP | S_IXOTH))
                    throwFromErrno(fmt::format("Cannot chmod {}", main_bin_tmp_path.string()), ErrorCodes::SYSTEM_ERROR);
                out.finalize();
            }
            catch (const Exception & e)
            {
                if (e.code() == ErrorCodes::CANNOT_OPEN_FILE && geteuid() != 0)
                    std::cerr << "Install must be run as root: sudo ./clickhouse install\n";
                throw;
            }
            if (old_binary_exists)
            {
                fmt::print("{} already exists, will rename existing binary to {} and put the new binary in place\n",
                        main_bin_path.string(), main_bin_old_path.string());