Fix executor tries to create a new deployment when a function is updated (#524)

Newdeploy manager now checks the existence of function service cache by function UID before trying to create a new deployment. And return the cached fsvc directly if the cache exists.

test/test_utils.sh

@@ -176,7 +176,7 @@ helm_install_fission() {
     helm list -q|xargs -I@ bash -c "helm_uninstall_fission @"
 
     # deleting ns does take a while after command is issued
-    while `kubectl get ns| grep "fission-builder"`
+    while kubectl get ns| grep "fission-builder"
     do
         sleep 5
     done
@@ -460,4 +460,4 @@ install_and_test() {
 #     echo "Usage: test.sh [image] [imageTag]"
 #     exit 1
 # fi
-# install_and_test $1 $2
+# install_and_test $1 $2