git: openjdk/skara: Add ReadOnlyRepository::contains

[duke]

Changeset: 25a8f8fa
Author:    Erik Helin <ehelin at openjdk.org>
Date:      2019-08-29 08:40:00 +0000
URL:       https://github.com/openjdk/skara/commit/25a8f8fa

Add ReadOnlyRepository::contains

Reviewed-by: rwestberg

! jcheck/src/test/java/org/openjdk/skara/jcheck/TestRepository.java
! vcs/src/main/java/org/openjdk/skara/vcs/ReadOnlyRepository.java
! vcs/src/main/java/org/openjdk/skara/vcs/git/GitRepository.java
! vcs/src/main/java/org/openjdk/skara/vcs/hg/HgRepository.java
! vcs/src/test/java/org/openjdk/skara/vcs/RepositoryTests.java