Steps to reproduce
1. Setup a cluster with 1 KV nodes and 1 Eventing node
2. We need to simulate a scenario of bad connection between Data service (memcached process) and Eventing process. One way of doing so is to add firewall rule to block requests going to port 11210.
3. Deploy an eventing function with feed boundary "From Now".
Observation without fix:
Eventing function deploys even after a failed attempt at opening up DCP streams and failed checkpointing.
Observation with the fix:
Eventing function will remain in "deploying" state until the connection to KV node is back to normal.