Set the id of the operator group back to ID 5 and document it for a heads up.

The uid change was introduced in commit 77e79d3374

docs/UPDATING

@@ -1,3 +1,8 @@
+20181115:
+	The "operator" group resumes the ID 5 instead 0 which was a workaround
+	added with the change here on 20170218. This was a change to ease the
+	migration from "operator" to "wheel" as the root group.
+
 20170303:
 	The entire network stack has been replaced.  This requires two updates.
 	First, BEFORE rebooting, either before or after rebuilding the system,

etc/group

@@ -3,7 +3,7 @@ daemon:*:1:daemon
 kmem:*:2:root
 sys:*:3:root
 tty:*:4:root
-operator:*:0:root
+operator:*:5:root
 mail:*:6:
 bin:*:7:
 wsrc:*:9:
@@ -27,6 +27,8 @@ _tss:*:28:
 _gpio:*:29:
 _rtadvd:*:30:
 guest:*:31:root
+_unbound:*:32:
+_nsd:*:33:
 nobody:*:39:
 utmp:*:45:
 authpf:*:72: