Revert "MB-11919 Log sequence number difference in indexing"

This change was for debugging purpose and doesn't add much
value. Hence it would make sense to revert it to have the
logs less noisy.

This reverts commit ce07551ae81163f8645373c062468e932bee953a.

Change-Id: I8cdd8fa49ca4928dd8165d8787f476d34233e4b1
Reviewed-on: http://review.couchbase.org/40790
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Sarath Lakshman <sarath@couchbase.com>
Reviewed-by: Nimish Gupta <nimish@couchbase.com>