Fix prototype for cbsasl_refresh_main

Change-Id: I53f0092741d3d0ca0c68e3903f45fd77a5dd9b6a
Reviewed-on: http://review.couchbase.org/29328
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>