RFR: Add Mercurial mapping for skara command

[Erik Duveblad via github.com]

Hi all,

this small patch just adds a Mercurial (hg) mapping for the `skara` command (used for help and update).

Thanks,
Erik

PR. This commit for this pull request was pushed with `hg` :smile:

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Commits:
 - f6fabb17:	Add Mercurial mapping for skara command

Pull request:
https://git.openjdk.java.net/skara/pull/127

Webrev:
https://webrevs.openjdk.java.net/skara/127/webrev.00

Patch:
https://git.openjdk.java.net/skara/pull/127.diff

Fetch command:
git fetch https://git.openjdk.java.net/skara pull/127/head:pull/127