Fix unit test failure in cbsasl

Introduced when adding more return statuses

Change-Id: I7f43d117d47f481c89d32f777ce014f2520dca9b
Reviewed-on: http://review.couchbase.org/39992
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>