enableCrossVectorVersioning reports unable to retrieve max_cas for all vbuckets

Sync Gateway test framework hits an error of Unable to retrieve max_cas for all vbuckets.

The creation of a bucket is done via gocb API using CreateBucket API. After creating a bucket, we'll make a REST call to /pools/default/buckets/bucketName -d enableCrossVectorVersioning=true.

Occasionally, this REST call will return

status code, 503, output: Unable to retrieve max_cas for all vbuckets

This occurs quite regularly in our test framework, which:

• deletes three buckets from a previous run
• create three bucket buckets
  • CreateBucket succeeds
  • enableCrossVectorVersioning <-- step that fails
• do kv ops on bucket(s)
• sometimes flush bucket(s) but not required

Usually the first run will succeed and subsequent runs through these steps can fail. If you wait, the couchbase server will recover and you can create a new bucket and enableCrossVectorVersioning on this system.