log: reorder filters as a small optimization

Reorder the filters for the journald layer. This sets the LevelFilter
last, which means tracing can disable all log statements lower than the
current level without evaluating the LogContext::exists function.

Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
 [ TL: note that this is just an optimization in the subject ]
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

proxmox-log/src/lib.rs

@@ -52,10 +52,10 @@ pub fn init_logger(
         .with(
             tracing_journald::layer()
                 .expect("Unable to open syslog")
-                .with_filter(log_level)
                 .with_filter(filter_fn(|metadata| {
                     LogContext::exists() || *metadata.level() == Level::ERROR
-                })),
+                }))
+                .with_filter(log_level),
         )
         .with(TasklogLayer {}.with_filter(log_level));