Initialize the number of items in wxSelectionStore.

wxSelectionStore::m_count was somehow never initialized, and even although
this seems harmless right now, don't leave it uninitialized if only to avoid
Valgrind warnings about using this.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@75094 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/selstore.h

@@ -80,7 +80,7 @@ public:
 
 private:
     // (re)init
-    void Init() { m_defaultState = false; }
+    void Init() { m_count = 0; m_defaultState = false; }
 
     // the total number of items we handle
     unsigned m_count;