GOCBC-597: Don't set replicaNumber for memcached buckets

Motivation
----------
As of 6.5 when creating a bucket the server will error if
the replicaNumber field is present for memcached buckets.

Changes
-------
On bucket create/edit check if replicaNumber is set to 0 and
it's a memcached bucket. If so then omit the field.

Change-Id: I0cdac80d044dd1ef7770e3657f4df10cd0b0573a
Reviewed-on: http://review.couchbase.org/114697
Reviewed-by: Brett Lawson <brett19@gmail.com>
Tested-by: Charles Dixon <chvckd@gmail.com>

cluster_bucketmgr.go

@@ -528,15 +528,18 @@ func (bm *BucketManager) settingsToPostData(settings *BucketSettings) (url.Value
 		posts.Add("replicaIndex", "1")
 	}
 
-	posts.Add("replicaNumber", fmt.Sprintf("%d", settings.NumReplicas))
-
 	switch settings.BucketType {
 	case CouchbaseBucketType:
 		posts.Add("bucketType", string(settings.BucketType))
+		posts.Add("replicaNumber", fmt.Sprintf("%d", settings.NumReplicas))
 	case MemcachedBucketType:
 		posts.Add("bucketType", string(settings.BucketType))
+		if settings.NumReplicas > 0 {
+			return nil, configurationError{message: "replicas cannot be used with memcached buckets"}
+		}
 	case EphemeralBucketType:
 		posts.Add("bucketType", string(settings.BucketType))
+		posts.Add("replicaNumber", fmt.Sprintf("%d", settings.NumReplicas))
 	default:
 		return nil, bucketManagerError{message: "Unrecognized bucket type"}
 	}