make: do not rm version header in criu make

It's generated and cleaned in the top Makefile.
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/Makefile

@@ -124,7 +124,6 @@ mrproper: subclean
 	$(Q) $(MAKE) $(call build-as,Makefile.crtools,.) $@
 	$(Q) $(MAKE) $(build)=pie/piegen $@
 	$(Q) $(MAKE) $(build)=pie $@
-	$(Q) $(RM) $(VERSION_HEADER)
 	$(Q) $(RM) $(CONFIG_HEADER)
 .PHONY: mrproper