Since vpp_sswan plugin already merged in /vpp/extras/strongswan,
no need to provide additional vpp_sswan source files for docker image.
Type: fix
Signed-off-by: Yulong Pei <yulong.pei@intel.com>
Change-Id: I35bad22b1046e0dddbcf39e1af38d589d1438239
Signed-off-by: Yulong Pei <yulong.pei@intel.com>