test/vhost: check vhost return code in spdk_vhost_kill

if vhost retuns error on exit using spdk_vhost_kill, the tests
would continue instead failing

Change-Id: I923d579f9e8614c39b27186418439d185770b3a7
Signed-off-by: Pawel Niedzwiecki <pawelx.niedzwiecki@intel.com>
Reviewed-on: https://review.gerrithub.io/398622
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>

test/vhost/common/common.sh

@@ -157,6 +157,9 @@ function spdk_vhost_kill()
 			rm $vhost_pid_file
 			return 1
 		fi
+
+		#check vhost return code, activate trap on error
+		wait $vhost_pid
 	elif /bin/kill -0 $vhost_pid; then
 		error "vhost NOT killed - you need to kill it manually"
 		return 1