arm builds fail to fetch pages

[clach04]

Possibly related to #346
Using prebuilt v0.8.0 arm64 and self built headrevs from master with arm6 (32-bit) database add, import, serve works fine. E.g.

 ./shiori-linux-arm64_download add https://github.com/go-shiori/shiori # downloaded from https://github.com/techknowlogick/shiori/releases/tag/v0.8.0
 ./shiori add https://github.com/go-shiori/shiori  # self-built

update to fetch warc/etc. fails with:

Failed to fetch https://github.com/go-shiori/shiori: the page is not readable

Upstream headrevs of shiori on same machine works fine.

[techknowlogick]

I've just ordered some arm hardware so I can debug this.