RFR: cli: skara debug import-git should always save marks

[Erik Helin]

Hi all,

please review this patch that makes `git skara debug import-git` always save the marks that were created as part of a
conversion, even though the conversion might have failed. This allows for incremental git imports.

Testing:
- [x] Manual testing on Linux x64

Thanks,
Erik

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Commit messages:
 - cli: hg-openjdk-import should always save marks

Changes: https://git.openjdk.java.net/skara/pull/737/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=737&range=00
  Stats: 35 lines in 2 files changed: 23 ins; 0 del; 12 mod
  Patch: https://git.openjdk.java.net/skara/pull/737.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/737/head:pull/737

PR: https://git.openjdk.java.net/skara/pull/737