pie/vdso: return back ELF header mismatch error

I've deleted it previously by the reason that I searched
vdso vma in [vdso/vvar] vma's pair by magic header.
So, I needed to suppress this error.

>From that moment, I've reworked how 32-bit vdso is parsed
and now we don't need to search it, even more: we parse it
only once in the criu helper.
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/pie/util-vdso.c

@@ -87,8 +87,11 @@ static int has_elf_identity(Ehdr_t *ehdr)
 
 	BUILD_BUG_ON(sizeof(elf_ident) != sizeof(ehdr->e_ident));
 
-	if (memcmp(ehdr->e_ident, elf_ident, sizeof(elf_ident)))
+	if (memcmp(ehdr->e_ident, elf_ident, sizeof(elf_ident))) {
+		pr_err("ELF header magic mismatch\n");
 		return false;
+	}
+
 	return true;
 }