Add cleanup function to make the build.sh more robust

cluster/ubuntu-cluster/build.sh

@@ -17,9 +17,15 @@
 # Download the etcd, flannel, and K8s binaries automatically
 # Run as root only
 
-# author @resouer
+# author @resouer @WIZARD-CXY
 set -e
 
+function cleanup {
+    # cleanup work
+    rm -rf flannel kubernetes* etcd* binaries
+}
+trap cleanup SIGHUP SIGINT SIGTERM
+
 # check root
 if [ "$(id -u)" != "0" ]; then
     echo >&2 "Please run as root"