Async callback needs to sync with the send event

Signed-off-by: John Else <john.else@citrix.com>
Revert "xenlight: replace Xenctrl.domain_setmaxmem with xenlight equivalent"

This reverts commit 4558b23c91a55ffa4d2325ffb8d51709b8fe5a63.

We need to first upstream this libxl binding.

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
Move xenctrl_uuid from xc to lib

And add handle_of_uuid function.

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
Update to new xenlight bindings

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
Xenlight events: add logging to async callback

Signed-off-by: John Else <john.else@citrix.com>
Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
Xenlight events: handle timeouts properly

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
CP-6226: Switch to calling async operations

The unfortunate exception is still domain_create(_new), which experiences
segfaults when run asynchronously.

However, this should not prevent concurrency anymore in the new libxl bindings.

Signed-off-by: John Else <john.else@citrix.com>
Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
Merge pull request #48 from robhoes/xen-unstable

Update to new libxl bindings, and switch to async ops