firewall: T2199: enable "auto-merge" on sets
firewall: T2199: enable "auto-merge" on sets

vyos@vyos# show firewall
+name foo {
+    rule 1 {
+        action accept
+        packet-length 100
+        packet-length 105
+        packet-length 200-300
+        packet-length 220-250
+    }
+}

will report a nftables error upon load: Error: conflicting intervals specified

With nftables 1.0.3 there is an "auto-merge" option which corrects this:
https://lwn.net/Articles/896732/

vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x