No real changes, just suppress a harmless warning.

g++ warned about possibly uninitialized variable, so initialize it in its
declaration even if it was actually already always initialized in the branches
where it could be used.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73548 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775