Fix side-effect in assertion.
Fix side-effect in assertion.

Change-Id: I87cafd977a68c8ac263b5a305def9cadc6ce01d0
Reviewed-on: http://review.northscale.com/1775
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>
Tested-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>

zbase/vbucketmigrator,zbase/vbucketmigrator,membase/vbucketmigrator,membase/vbucketmigrator,zbase/vbucketmigrator,membase/vbucketmigrator,zbase/vbucketmigrator,membase/vbucketmigrator