Adjust pointer tracking to assist static checkers

Coverity scanning struggles to follow our 'super' handling
under certain circumstances.  Adjust the code to ensure we
keep good coverage even though this is a false positive.

pcp/InDomTable.c

@@ -73,7 +73,7 @@ static void InDomTable_goThroughEntries(InDomTable* this) {
       Instance* inst = InDomTable_getInstance(this, instid, &preExisting);
       inst->offset = offset >= 0 ? offset : 0;
 
-      Row* row = &inst->super;
+      Row* row = (Row*) inst;
       if (!preExisting)
          Table_add(super, row);
       row->updated = true;