OpenZFS 2.2+ breaks the zfs.py script

[syntaxerrormmm]

As it is described here and more deeply here, it seems the ARC metadata mangling has changed.

The clearest consequence is that the parameter arc_meta_limit is not anymore shown in /proc/spl/kstat/zfs/arcstats, breaking the script zfs.py:

Traceback (most recent call last):
  File "/usr/lib/zabbix/externalscripts/agent/zfs.py", line 194, in <module>
    'arc': arc_stats(),
           ^^^^^^^^^^^
  File "/usr/lib/zabbix/externalscripts/agent/zfs.py", line 173, in arc_stats
    'meta_limit': r['arc_meta_limit'],
                  ~^^^^^^^^^^^^^^^^^^
KeyError: 'arc_meta_limit'

The quick and dirty workaround is to comment line 173 in zfs.py, making the script work again.

Of course, this deeply breaks items and triggers depending on key zfs.arc.l1.meta_limit inside the template, but at least the rest of the template continues to work fine.