bug#10164: 24.0.91; Instant crash enabling linum-mode

[Eli Zaretskii]

> From: Juanma Barranquero <lekktu@gmail.com>
> Date: Wed, 30 Nov 2011 13:38:17 +0100
> Cc: Tim Crews <tim.crews@code-affinity.com>, Chong Yidong <cyd@gnu.org>, 
> 10164@debbugs.gnu.org
> 
> But verify_row_hash does nothing except checking and returning a flag,
> so the new code will never cause an assertion failure...

*Blush*

Thanks for fixing, I somehow managed to delete the xassert itself..