VPP version used:

[root@rhel-test build]# vppctl show version
vpp v16.09-rc0~371-gc53191d~b2 built by jenkins on centos-7-29b at Mon Aug 15 14:01:12 UTC 2016

Seems that vhost-user CLI is missing:

[root@rhel-test build]# vppctl create vhost socket /tmp/sock1 feature-mask 0xFF
create: unknown input `vhost socket /tmp/sock1 featur...'
[root@rhel-test build]# vppctl show vhost-user
show: unknown input `vhost-user'

API, on the other hand, seems OK:

[root@rhel-test build]# echo create_vhost_user_if socket /tmp/sock2 | vpp_api_test
vat# vat#
[root@rhel-test build]#
[root@rhel-test build]# vppctl show int
Name Idx State Counter Count
[...]
VirtualEthernet0/0/0 4 down
[...]