Use cbsasl instead of isasl

Change-Id: I441cee610fc95964cdee8d4d3fd8f4d382772c74
Reviewed-on: http://review.couchbase.org/28675
Reviewed-by: Michael Wiederhold <mike@couchbase.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>