Sequence numbers issue with an index that survives an upgrade to 7.0

Take this scenario ..

• 1 node (KV, search) on pre-7.0
• Bucket with 3 items in vb_0
• Setup an FTS index for the bucket, uses source:go-couchbase
• seq 3 will be the highest received seq number for vb_0
• Upgrade node, index continues to use go-couchbase for DCP
• Now create a collection within the _default scope and insert an item into it.
• The index which still uses go-couchbase for DCP will indicate that the highest seqno received for vb_0 is 3 but will report the highest seqno for vb_0 on source is 5. This is because go-couchbase feeds do NOT interpret collections at the moment.