pages: Accept pages images from versions v0.4 and below

After reworkring the way pagemap is stored the backward compatibility
was not preserved for patches simplicity. Time to return it back.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

include/crtools.h

@@ -86,6 +86,9 @@ enum {
 	CR_FD_PAGES,
 	CR_FD_PSIGNAL,
 
+	CR_FD_PAGES_OLD,
+	CR_FD_SHM_PAGES_OLD,
+
 	CR_FD_MAX
 };