get rid of unnecessary method in class StructureArray

pvDataApp/factory/Compare.cpp

@@ -85,7 +85,7 @@ bool operator==(const Structure& a, const Structure& b)
 
 bool operator==(const StructureArray& a, const StructureArray& b)
 {
-    return a.structure() == b.structure();
+    return a.getStructure().get()==b.getStructure().get();
 }
 
 namespace nconvert {

pvDataApp/pv/pvIntrospect.h

@@ -332,7 +332,6 @@ public:
     typedef StructureArray& reference;
     typedef const StructureArray& const_reference;
 
-    const Structure& structure() const {return *pstructure;}
     /**
      * Get the introspection interface for the array elements.
      * @return The introspection interface.