CCBC-228, CCBC-229: Fix get replica on negative replies

Change-Id: Ic3e03adb91852e7755bd05e8899d2caf017436e7
Reviewed-on: http://review.couchbase.org/27492
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>