`filelock.py` Error
## Describe the bug

It seems that the `filelock.py` went error. 

```
>>> ds=load_dataset('xsum')

^CTraceback (most recent call last):
  File "/user/HS502/yl02706/.conda/envs/lyc/lib/python3.6/site-packages/datasets/utils/filelock.py", line 402, in _acquire
    fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
OSError: [Errno 37] No locks available
```

According to error log, it is OSError, but there is an `except` in the `_acquire` function.

```
    def _acquire(self):
        open_mode = os.O_WRONLY | os.O_CREAT | os.O_EXCL | os.O_TRUNC
        try:
            fd = os.open(self._lock_file, open_mode)
        except (IOError, OSError):
            pass
        else:
            self._lock_file_fd = fd
        return None
```

I don't know why it stucked rather than `pass` directly.

I am not quite familiar with filelock operation, so any help is highly appriciated.

## Steps to reproduce the bug
```python

ds = load_dataset('xsum')
```

## Expected results
A clear and concise description of the expected results.

## Actual results
```
>>> ds=load_dataset('xsum')

^CTraceback (most recent call last):
  File "/user/HS502/yl02706/.conda/envs/lyc/lib/python3.6/site-packages/datasets/utils/filelock.py", line 402, in _acquire
    fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
OSError: [Errno 37] No locks available

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/user/HS502/yl02706/.conda/envs/lyc/lib/python3.6/site-packages/datasets/load.py", line 818, in load_dataset
    use_auth_token=use_auth_token,
  File "/user/HS502/yl02706/.conda/envs/lyc/lib/python3.6/site-packages/datasets/load.py", line 470, in prepare_module
    with FileLock(lock_path):
  File "/user/HS502/yl02706/.conda/envs/lyc/lib/python3.6/site-packages/datasets/utils/filelock.py", line 323, in __enter__
    self.acquire()
  File "/user/HS502/yl02706/.conda/envs/lyc/lib/python3.6/site-packages/datasets/utils/filelock.py", line 272, in acquire
    self._acquire()
  File "/user/HS502/yl02706/.conda/envs/lyc/lib/python3.6/site-packages/datasets/utils/filelock.py", line 402, in _acquire
    fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
KeyboardInterrupt
```

## Environment info
<!-- You can run the command `datasets-cli env` and copy-and-paste its output below. -->

- `datasets` version: 1.9.0
- Platform: Linux-4.15.0-135-generic-x86_64-with-debian-buster-sid
- Python version: 3.6.13
- PyArrow version: 4.0.1
