x86/32: don't unmap vdso_rt after redirecting calls there

We need to leave this part of restorer in restored task in case
of inserted redirected calls. Jump trampolines from old vdso lead
here - it would be painful to land nowhere.
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/pie/restorer.c

@@ -935,6 +935,7 @@ asm (
 	"	.code32\n"
 	"	mov bootstrap_start, %ebx\n"
 	"	mov bootstrap_len, %ecx\n"
+	"	sub vdso_rt_size, %ecx\n"
 	"	movl $"__stringify(__NR32_munmap)", %eax\n"
 	"	int	$0x80\n"
 	"	.code64\n"