Restore socket initialization times counter.

Restore socket initialization times counter.

The change of the counter to a simple boolean in r61985 broke the code which
called both Initialize() and Shutdown() multiple (but the same number of)
times. As this is the documented correct behaviour, restore the counter to
cater for it even if we don't really need it any longer.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@61998 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775