Re: libostree 2018.9

[Colin Walters <walters verbum org>]

Turns out we broke builds from the tarball in this release:
https://github.com/ostreedev/ostree/pull/1766

Doesn't affect people using git directly (as I hope most are).
I have rolled a new tarball though as 2018.9.01.tar.xz and
attached it to the release:
https://github.com/ostreedev/ostree/releases/download/v2018.9/libostree-2018.9.1.tar.xz
The version remains 2018.9 in the code.

And we've added a CI check to avoid this in the future.