MB-7542: Set seq_id to 1 if not set or as zero

For offline upgrade or data restore, set seq_id to 1 when it is not set
or set as zero.

Change-Id: I5ff72068dfb07026e6cc528bf467055bcfe8b00f
Reviewed-on: http://review.couchbase.org/24003
Reviewed-by: Steve Yen <steve.yen@gmail.com>
Tested-by: Bin Cui <bin.cui@gmail.com>