Fully resolves the path to /etc/localtime on the host.
Fully resolves the path to /etc/localtime on the host.

Fixes #145.  Also affects #142: `usr` is no longer a child of `rootfs`
and `manifest` in `.acbuild/currentaci`.

appc/acbuild,dgonyeo/acbuild,jonboulle/acbuild,mikeln/acbuild,asbachb/acbuild,containers/build,joshix/acbuild,containers/build,dgonyeo/acbuild,joshix/acbuild,asbachb/acbuild,appc/acbuild,mikeln/acbuild,jonboulle/acbuild