Coverity issues:

129727: Structurally dead code
151979, 133461: Uninitialized scalar field
129785, 129786, 129787: Use after free

src/App/Expression.cpp

@@ -773,7 +773,7 @@ private:
 
 class StdDevCollector : public Collector {
 public:
-    StdDevCollector() : Collector() { }
+    StdDevCollector() : Collector(), n(0) { }
 
     void collect(Quantity value) {
         Collector::collect(value);