Import vhost_server.c

Import the whole vhost_user control infrastucture in C.
This provides creating and polling a vhost-user (unix domain socket based)
server to handle messages from a vhost-user client.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
vhost_apps selftest use 1000 preallocated buffers

The large number of buffers exhausts the available huge pages on the machine.
We want to have available pages for qemu to allocate with -mem-path -mem-prealloc

Increase the sleep time fo the test so we can connect with qemu

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>