Add support for CloseStream

Change-Id: Ied6e2e0611d737da3cd6a146ffc2c31b0666a7f8
Reviewed-on: http://review.couchbase.org/30685
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>