RFR: 55: Reduce disk usage for notify bot

[Robin Westberg via github.com]

Hi all,

Please review this change that decreases the disk usage for the notifier bot.

Best regards,
Robin

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Commits:
 - 75db5502:	Use storage for materializing repos, avoid checkouts

Pull request:
https://git.openjdk.java.net/skara/pull/42

Webrev:
https://webrevs.openjdk.java.net/skara/42/webrev.00

Patch:
https://git.openjdk.java.net/skara/pull/42.diff

Fetch command:
git fetch https://git.openjdk.java.net/skara pull/42/head:pull/42