Improve travi-ci test scripts (#434)

Make our travis-based integration test less flaky:

* Wait for tiller ready before installation

* Remove all existing old releases before installation

test/test_utils.sh

@@ -12,7 +12,16 @@ ROOT=$(dirname $0)/..
 
 helm_setup() {
     helm init
+    # wait for tiller ready
+    while true; do
+      kubectl --namespace kube-system get pod|grep tiller|grep Running
+      if [[ $? -eq 0 ]]; then
+          break
+      fi
+      sleep 1
+    done
 }
+export -f helm_setup
 
 gcloud_login() {
     KEY=${HOME}/gcloud-service-key.json
@@ -137,10 +146,10 @@ helm_install_fission() {
 
     helmVars=image=$image,imageTag=$imageTag,fetcherImage=$fetcherImage,fetcherImageTag=$fetcherImageTag,functionNamespace=$fns,controllerPort=$controllerNodeport,routerPort=$routerNodeport,pullPolicy=Always,analytics=false,logger.fluentdImage=$fluentdImage
 
-    helm_setup
+    timeout 30 helm_setup
 
-    echo "Deleting failed releases"
-    helm list --failed -q|xargs -I@ bash -c "helm delete @"
+    echo "Deleting old releases"
+    helm list -q|xargs helm_uninstall_fission
     
     echo "Installing fission"
     helm install		\
@@ -188,6 +197,7 @@ helm_uninstall_fission() {
     echo "Uninstalling fission"
     helm delete --purge $1
 }
+export -f helm_uninstall_fission
 
 set_environment() {
     id=$1