Update of VPP_STABLE_VER files and DPDK_STABLE_VER file

- use new vpp ref build - ubuntu 16.04:
  18.01-rc0~156-gae5a02f~b3093_amd64

- use new vpp ref build - centos7:
  18.01-rc0~156_gae5a02f~b3090.x86_64

- use new dpdk version:
  17.08-vpp2

- builds tested by semiweekly jobs:
  https://jenkins.fd.io/view/csit/job/csit-vpp-verify-master-ubuntu1604-semiweekly/85/
  https://jenkins.fd.io/view/csit/job/csit-vpp-verify-master-centos7-semiweekly/85/

- remove vpp-debuginfo centos7 artifact as not provided for new versions

Change-Id: I18445feac98304e7e7ecdf77968acebf2d5aef09
Signed-off-by: Jan Gelety <jgelety@cisco.com>