[libvirt] [PATCHv4 0/4] qemu aio support

In looking for other examples of XML additions, I noticed commit 8bf6799 was the last of a four-patch series for adding timer support. I'm reposting this into a split series, but still leaving attribution to Matthias, since the text of the result is still very close to his original submission. [PATCHv4 1/4] qemu aio: add XML parsing [PATCHv4 2/4] qemu aio: add aio attribute to schema [PATCHv4 3/4] qemu aio: parse aio support from qemu -help [PATCHv4 4/4] qemu aio: enable support