s3:smb2_server: make sure we grant credits on async read/write operations (bug #8357)

s3:smb2_server: make sure we grant credits on async read/write operations (bug #8357)

Currently we skip, the "gone async" interim response on read and write,
this caused the aio code path to grant 0 credits to the client
in the read/write responses.

metze

Autobuild-User: Stefan Metzmacher <metze@samba.org>
Autobuild-Date: Sun Aug  7 22:23:57 CEST 2011 on sn-devel-104
(cherry picked from commit 47bffb9b9243dc72d7305cd9ec3e63e176841bf5)
(cherry picked from commit cbd408df89ec51fb06fbfb935458eb8425639bed)