traverser: add support for planner reinitialization

Problem: traverser has no means of reinitialization for an existing
planner. Elastic operations like attach and remove require planner
reinitialization. Running basic initialization will remove counts for
resources scheduled.

Check to see if the planner exists and update it (reinitialize).
Create a new planner if it doesn't (initialize).

Author: zekemorton

resource/traversers/dfu_impl.cpp

@@ -1132,7 +1132,12 @@ int dfu_impl_t::prime_pruning_filter (const subsystem_t &s, vtx_t u,
         }
     }
 
-    if (!avail.empty () && !types.empty ()) {
+    if (avail.empty () || types.empty ()) {
+        rc = 0;
+        goto done;
+    }
+
+    if ( (*m_graph)[u].idata.subplans[s] == NULL) {
         errno = 0;
         planner_multi_t *p = NULL;
         if (!(p = subtree_plan (u, avail, types)) ) {
@@ -1141,6 +1146,9 @@ int dfu_impl_t::prime_pruning_filter (const subsystem_t &s, vtx_t u,
             goto done;
         }
         (*m_graph)[u].idata.subplans[s] = p;
+    } else {
+        planner_multi_update ((*m_graph)[u].idata.subplans[s], &avail[0], 
+                               &types[0], types.size ());
     }
     rc = 0;
 done: