including also Haiku) using FIFOs instead of Unix sockets. Advantages:
* Multiple FS shells can run concurrently, since they no longer need a unique
address.
* Killing/aborting the build_haiku_image script will automatically tear down
the FS shell as well, so there shouldn't be any stray FS shell processes
anymore. Hopefully also fixes#5498.
So far only tested under Haiku.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@40097 a95241bf-73f2-0310-859d-f6bbb57e9c96