warning C4018: '<' : signed/unsigned mismatch

Change-Id: I5e6a6debf01886c283f5a2d6b9cacc00a44f7134

slideshow/source/engine/opengl/TransitionImpl.hxx

@@ -338,7 +338,7 @@ public:
 
     int getVerticesCount() const
     {
-        assert(Vertices.size() < std::numeric_limits<int>::max());
+        assert(Vertices.size() < unsigned(std::numeric_limits<int>::max()));
         return int(unsigned(Vertices.size()));
     }