The 'make' creates all required variants of vSwitch

The 'make' creates all required variants of vSwitch

Currently the VSPERF makefiles make just one variant
of vSwitch - OVS with DPDK-vhost-user. To make the other
variants the makefile has to be edited. And the make re-run.
The fix builds all required versions:
DPDK-vhost-user OVS (in src/)
Vanilla OVS (in src_vanilla/)
DPDK-vhost-cuse OVS (in src_cuse/)
HowTo:
- git clone vsperf
- cd .../src
- make

JIRA: VSPERF-85

Change-Id: I469baf8432f0b127cde785f35a6c57a2c778f23f
Signed-off-by: Radek Zetik <radekx.zetik@intel.com>
Reviewed-by: Maryam Tahhan <maryam.tahhan@intel.com>
Reviewed-by: Brian Castelli <brian.castelli@spirent.com>