Prevent unused warning.

test/ScopeFailTest.cpp

     {
         REQUIRE_CALL(m, deleter());
         auto guard = sr::make_scope_fail(deleter);
+        static_cast<void>(guard);
         throw 3;
     }
     catch( ... )
     catch( ... )
     {
         auto guard = sr::make_scope_fail(deleter);
+        static_cast<void>(guard);
     }
 }
 

test/ScopeSuccessTest.cpp

     try
     {
         auto guard = sr::make_scope_success(deleter);
+        static_cast<void>(guard);
         throw 3;
     }
     catch( ... )
     {
         REQUIRE_CALL(m, deleter());
         auto guard = sr::make_scope_success(deleter);
+        static_cast<void>(guard);
     }
 }