RFR: checkout-bot: remote leading slash from path

[Erik Helin]

Hi all,

please review this patch that removes the leading slash from the path to the marks file for the checkout bot.

Testing:
- `make test` passes on Linux x64
- Manual testing on Linux x64

Thanks,
Erik

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Commit messages:
 - checkout-bot: remote leading slash from path

Changes: https://git.openjdk.java.net/skara/pull/759/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=759&range=00
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/skara/pull/759.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/759/head:pull/759

PR: https://git.openjdk.java.net/skara/pull/759