HGKeeper

Fix the build when ran in a meson subproject.
feature/meson-subproject-fix
2019-08-12, Gary Kramlich

923cbd2a8055

Fix the build when ran in a meson subproject.

We were using meson.build_root() when we should have been using
meson.current_build_dir().

[branchname]

master = default

develop = develop

feature = feature/

release = release/

hotfix = hotfix/

support = support/