Destructor for wxMimeTypesManager was deleting its member m_impl without checking if it was already NULL or not.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@9239 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/mimecmn.cpp

@@ -414,7 +414,8 @@ wxMimeTypesManager::wxMimeTypesManager()
 
 wxMimeTypesManager::~wxMimeTypesManager()
 {
-    delete m_impl;
+    if ( m_impl )
+        delete m_impl;
 }
 
 wxFileType *