qmake: remove pointless ~VCProjectSingleConfig()

It's empty, but non-trivial, thus preventing move special member
functions from being generated by the compiler (now that qmake
is compiled as C++11, too).

The default ctor was also empty - removed, too.

Change-Id: I714db524f681f1fc250d21926245757e97351e87
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>

qmake/generators/win32/msvc_objectmodel.h

@@ -974,9 +974,6 @@ public:
         Resources,
         Extras
     };
-    // Functions
-    VCProjectSingleConfig(){}
-    ~VCProjectSingleConfig(){}
 
     // Variables
     QString                 Name;