Add a match test for vhost_target show_details method. In spdkcli source the equivalent function is `UIVhostTargetObj.show_details`. This method is one of few that left untested in spdkcli. This patch is related to trello task: https://trello.com/c/CHOOxcGj/151-spdkcli-extend-test-coverage Change-Id: I3747b0bef4a54606765c81a003bbc9e12fe32858 Signed-off-by: Vitaliy Mysak <vitaliy.mysak@intel.com> Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/463281 Tested-by: SPDK CI Jenkins <sys_sgci@intel.com> Reviewed-by: Paul Luse <paul.e.luse@intel.com> Reviewed-by: Ben Walker <benjamin.walker@intel.com> Reviewed-by: Jim Harris <james.r.harris@intel.com>