"sw_interface_vhost_user_dump" returns always 0 "sw_interface_vhost_user_details" elements. No error is returned from sw_interface_vhost_user_dump.

This is a blocker for FDS use case which relies on honeycomb and honeycomb relies on VPP's sw_interface_vhost_user_dump when reading vhost user interface details.

Can be replicated using VAT:
"sw_interface_vhost_user_dump" from VAT always returns zero elements even if any number of vhost user interfaces are created beforehand using create_vhost_user_if.

On both 16.09:
Version: v16.09-rc1
Compiled by: mmarsale
Compile host: mmarsale-VirtualBox
Compile date: Tue Aug 23 17:37:59 CEST 2016
Compile location: /home/mmarsale/Projects/vpp
Compiler: GCC 5.2.1 20151010
CPU model name: Intel(R) Core(TM) i7-4810MQ CPU @ 2.80GHz
CPU microarchitecture: Haswell (Haswell)
CPU flags: sse3 ssse3 sse41 sse42 avx aes
Current PID: 4017
DPDK Version: DPDK 16.07.0
DPDK EAL init args: -c 1 -n 4 --huge-dir /run/vpp/hugepages --file-prefix vpp -b 0000:00:03.0 -b 0000:00:08.0 -b 0000:00:09.0 --master-lcore 0 --socket-mem 256

and also master:
Version: v16.12-rc0~12-g3a83460
Compiled by: m
Compile host: m-VirtualBox
Compile date: St aug 24 08:00:44 CEST 2016
Compile location: /home/m/vpp_master/vpp
Compiler: GCC 4.9.2
CPU model name: Intel(R) Core(TM) i7-4810MQ CPU @ 2.80GHz
CPU microarchitecture: Haswell (Haswell)
CPU flags: sse3 ssse3 sse41 sse42 avx aes
Current PID: 10134
DPDK Version: DPDK 16.07.0
DPDK EAL init args: -c 1 -n 4 --huge-dir /run/vpp/hugepages --file-prefix vpp -b 0000:00:03.0 --master-lcore 0 --socket-mem 256