Jail mount point failure

Got this trying to fix plex jail

```Error: Traceback (most recent call last):
File "/usr/local/lib/python3.7/site-packages/middlewared/plugins/jail.py", line 1275, in fstab
dump, _pass, index=index
File "/usr/local/lib/python3.7/site-packages/iocage_lib/iocage.py", line 1135, in fstab
index=index
File "/usr/local/lib/python3.7/site-packages/iocage_lib/ioc_fstab.py", line 86, in _init_
self._fstab_parse_()
File "/usr/local/lib/python3.7/site-packages/iocage_lib/ioc_fstab.py", line 128, in _fstab_parse_
self._validate_fstab_([self.mount], actions=['replace'])
File "/usr/local/lib/python3.7/site-packages/iocage_lib/ioc_fstab.py", line 316, in _validate_fstab_
exception=iocage_lib.ioc_exceptions.ValidationFailed
File "/usr/local/lib/python3.7/site-packages/iocage_lib/ioc_common.py", line 103, in logit
callback(content, exception)
File "/usr/local/lib/python3.7/site-packages/iocage_lib/ioc_common.py", line 76, in callback
raise callback_exception(message)
iocage_lib.ioc_exceptions.ValidationFailed: ['Dump: ro must be a digit!', 'Dump: ro must be one digit long!']

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/usr/local/lib/python3.7/site-packages/middlewared/main.py", line 130, in call_method
io_thread=False)
File "/usr/local/lib/python3.7/site-packages/middlewared/main.py", line 1095, in _call
return await run_method(methodobj, *args)
File "/usr/local/lib/python3.7/site-packages/middlewared/main.py", line 1019, in _run_in_conn_threadpool
return await self.run_in_executor(self.__ws_threadpool, method, *args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/middlewared/main.py", line 1007, in run_in_executor
return await loop.run_in_executor(pool, functools.partial(method, *args, **kwargs))
File "/usr/local/lib/python3.7/concurrent/futures/thread.py", line 57, in run
result = self.fn(*self.args, **self.kwargs)
File "/usr/local/lib/python3.7/site-packages/middlewared/schema.py", line 965, in nf
return f(*args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/middlewared/plugins/jail.py", line 1287, in fstab
raise CallError(e.message)
middlewared.service_exception.CallError: [EFAULT] Dump: ro must be a digit!
Dump: ro must be one digit long!
```