Do not allow memcached buckets to be added as source while creating an eventing function.

1. Create a Vulcan cluster with data and eventing nodes.
2. Create 2 memcached buckets and a couchbase bucket
3. Open eventing function and try to create a function by choosing memcached bucket as the source. Choose couchbase bucket as meta bucket and 2nd memcached bucket as destination
4. Create the function and deploy. The deploy goes through fine.

The eventing logs now starts throwing Failed to get failover logs, err: dcp.invalidVbucket, which is expected since memcached has no DCP.
We should either not show the DCP buckets while creating functions or throw error while trying to deploy the function saying memcached buckets are not supported.
Currently, once the function is deployed, the function cannot be deleted or undeployed since eventing is still in bootstrap and never comes out of bootstrap.