Fix compilation warning about invalid deletion

Warnings were:
glide.h:74:16: warning: possible problem detected in invocation of delete operator:
glide.h:74:16: warning: invalid use of incomplete type 'struct QTimeLine'
glide.h:28:7: warning: forward declaration of 'struct QTimeLine'
glide.h:74:16: note: neither the destructor nor the class-specific operator delete will be called, even if they are declared when the class is defined.

effects/glide/glide.cpp

@@ -234,4 +234,9 @@ GlideEffect::WindowInfo::WindowInfo()
 {
 }
 
+GlideEffect::WindowInfo::~WindowInfo()
+{
+    delete timeLine;
+}
+
 } // namespace

effects/glide/glide.h

@@ -70,9 +70,7 @@ class GlideEffect::WindowInfo
 {
 public:
     WindowInfo();
-    ~WindowInfo() {
-        delete timeLine;
-    }
+    ~WindowInfo();
     bool deleted;
     bool added;
     bool closed;