remove unnecessary condition check for daemon status

```python
    os.getpgrp() != os.getpid()
```
IMHO the above statement is unnecessary and may be wrong under circumstance described below:

The command to launch gunicorn is written in a bash script. something like this:

    cat run.sh
    gunicorn app:app --max-requests 5000 

We execute ./run.sh to start gunicorn, therefore it is started under a shell process. Then os.getpgrp() equals the process id of the shell, not the process id of gunicorn, which makes the statement True and kills all workers when SIGWINCH is recevied.