e window list: prevent from segfaulting, patch from andrej.

Description from Trac (see #1020):

Pressing a key which is bound to "next/previous window of the same class" can make Enlightenment SEGV. This happens when:

    Window switcher list module is loaded
    the key is pressed when the active desktop is empty (i.e., contains no windows / applications) and at least one other desktop contains one or several windows 

This does not happen if all the desktops are empty.

 Fixes #1020.


SVN revision: 72753

src/modules/winlist/e_winlist.c

@@ -180,10 +180,12 @@ e_winlist_show(E_Zone *zone, E_Winlist_Filter filter)
         switch (filter)
           {
            case E_WINLIST_FILTER_CLASS_WINDOWS:
-             pick = !strcmp(_last_border->client.icccm.class,
-                            bd->client.icccm.class);
+             if (!_last_border)
+               pick = EINA_FALSE;
+             else
+               pick = !strcmp(_last_border->client.icccm.class,
+                              bd->client.icccm.class);
              break;
-
            case E_WINLIST_FILTER_CLASSES:
              pick = (!_wmclass_picked(wmclasses, bd->client.icccm.class));
              if (pick)