FIx potential segfault (CID 168)

(cherry picked from commit a5ad91e7)
Signed-off-by: Derk-Jan Hartman <hartman@videolan.org>

modules/misc/osd/simple.c

@@ -510,6 +510,7 @@ int osd_parser_simpleOpen( vlc_object_t *p_this )
 
 error:
     msg_Err( p_menu, "parsing file failed (returned %d)", result );
+    if( p_menu )
         osd_MenuFree( p_menu );
     fclose( fd );
     return VLC_EGENERIC;