CBQE-0: reduce not_my_vbucket logs output

Change-Id: I064341671c6865df4d84e47684cd590d5c359539
Reviewed-on: http://review.couchbase.org/31566
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: Iryna Mironava <irynamironava@yandex.ru>