NFSv4.1 don't free interrupted slot on open

NFSv4.1 don't free interrupted slot on open

BugLink: https://bugs.launchpad.net/bugs/1823060
commit 0cb98abb5bd13b9a636bde603d952d722688b428 upstream.

Allow the async rpc task for finish and update the open state if needed,
then free the slot. Otherwise, the async rpc unable to decode the reply.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Fixes: ae55e59da0e4 ("pnfs: Don't release the sequence slot...")
Cc: stable@vger.kernel.org # v4.18+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>