Don't remove the last slash from "/" directory name under Unix.

This was totally wrong as it returned empty string as (invalid) directory
name.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71353 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/unix/dir.cpp

@@ -235,10 +235,13 @@ wxString wxDir::GetName() const
     if ( m_data )
     {
         name = M_DIR->GetName();
-        if ( !name.empty() && (name.Last() == wxT('/')) )
+
+        // Notice that we need to check for length > 1 as we shouldn't remove
+        // the last slash from the root directory!
+        if ( name.length() > 1 && (name.Last() == wxT('/')) )
         {
-            // chop off the last (back)slash
-            name.Truncate(name.length() - 1);
+            // chop off the last slash
+            name.RemoveLast();
         }
     }