Fixed call of virtual from DTOR issue

Removed virtual and changed the only overrider of the virtual to
do the special case

Signed-off-by: Charlie Vigue <charlie.vigue@openvpn.com>

openvpn/common/scoped_fd.hpp

@@ -108,17 +108,12 @@ class ScopedFD
  {
  if (::close(fd) == -1)
  eno = errno;
- post_close(eno);
  // OPENVPN_LOG("**** SFD CLOSE fd=" << fd << " errno=" << eno);
  fd = -1;
  }
  return eno;
  }
 
- virtual void post_close(const int close_errno)
- {
- }
-
  virtual ~ScopedFD()
  {
  // OPENVPN_LOG("**** SFD DESTRUCTOR");