keep deferrals count in place betweeen mgr restarts

lib/App/Netdisco/Backend/Role/Manager.pm

@@ -21,6 +21,7 @@ sub worker_begin {
   debug "entering Manager ($wid) worker_begin()";
 
   # job queue initialisation
+  debug "mgr ($wid): building acl hints (please be patient...)";
   jq_warm_thrusters;
 
   # requeue jobs locally

lib/App/Netdisco/JobQueue/PostgreSQL.pm

@@ -57,14 +57,26 @@ sub jq_warm_thrusters {
   }
 
   schema('netdisco')->txn_do(sub {
-    $rs->search({ backend => setting('workers')->{'BACKEND'} })->delete;
+    $rs->search({
-    $rs->populate([
+      backend => setting('workers')->{'BACKEND'},
-      map {{
+    }, { for => 'update' }, )->update({ actionset => [] });
+
+    $rs->search({
+      backend => setting('workers')->{'BACKEND'},
+      deferrals => { '>' => 0 },
+    }, { for => 'update' }, )->update({ deferrals => \'deferrals - 1' });
+
+    $rs->search({
+      backend => setting('workers')->{'BACKEND'},
+      actionset => { -value => [] },
+      deferrals => 0,
+    })->delete;
+
+    $rs->update_or_create({
       backend => setting('workers')->{'BACKEND'},
       device  => $_,
       actionset => $actionset{$_},
-      }} keys %actionset
+    }, { key => 'primary' }) for keys %actionset;
-    ]);
   });
 }