Use path separator, not "/"

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_4_BRANCH@18445 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/html/helpctrl.cpp

@@ -176,7 +176,7 @@ bool wxHtmlHelpController::Initialize(const wxString& file)
     wxSplitPath(file, & dir, & filename, & ext);
 
     if (!dir.IsEmpty())
-        dir = dir + wxString(wxT("/"));
+        dir = dir + wxFILE_SEP_PATH);
 
     // Try to find a suitable file
     wxString actualFilename = dir + filename + wxString(wxT(".zip"));