deps: Update bundled lua client version

The new version fixes defunct processes which causes random test failures on
some systems(#1519)
Merge PR #1547 'Update bundled lua client version'
Add missing refcount increment for systemlist()

- get_system_output_as_rettv() was missing a refcount increment when
  returning an empty list, i.e. when there was no output
- we now use rettv_list_aloc() instead of list_alloc()
- issue #1530
Merge pull request #1552 from equalsraf/tb-fix-1530

add missing refcount increment for systemlist()