MB-11059: Offline upgrade - extended metadata

- While during an offline upgrade from pre 3.0 to
3.0. Extended metadata will not be set, as this is
a new feature in 3.0.

- This change is to identify documents during the
first compaction after an offline upgrade and set
the extended metadata for documents on disk
appropriately.

Change-Id: I8cefb5d57d9fa0ddcebb8f2fde95ba6189fda6a7
Reviewed-on: http://review.couchbase.org/37675
Reviewed-by: Sundararaman Sridharan <sundar@couchbase.com>
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: abhinav dangeti <abhinav@couchbase.com>