Galera sources changed

Hello,

Codership, the Galera upstream, changed the way they treat file 'wsrep_api.h'.
Commit:
https://github.com/codership/galera/commit/adc5bce1aa0dd4e69af7ab6b6bb76490a662be80

Basically thay added the file as a git submodule to their project, which leads to a state, where your downstream (MariaDB) Galera sources asre missing that file.

I recommend adjusting the source-making process of the Galera traball, so it carries the file again.

It would be inconvenient for me to build the Galera for Fedora from two sources - base tarball from MariaDB and wsrep_api.h file from Codership.
Nothing I couldn't solve downstream, but I believe it wasn't your intention to stop packing that file. You just didn't noticed.
So it would be nice to rather fix my upstream ( you )

Thank you