Bug#569436: bump severity

[Sylvestre Ledru]

> > Nevertheless, thanks Kumar and Sylvestre for the high-quality work on
> > investigating this.
> 
> Thank you for the report, and I hope we can solve it in a satisfactory
> manner.
I uploaded a version with -O2 for amd64 as a temporary workaround.
However, I haven't close this bug until we really fixed it.

Please confirm that it fixes your issue ;)
Thx
Sylvestre