virtio-blk: Fix clean up of host notifiers for single MR transaction.

virtio-blk: Fix clean up of host notifiers for single MR transaction.

The code that introduced "virtio-blk: Configure all host notifiers in
a single MR transaction" introduced a second loop variable to perform
cleanup in second loop, but mistakenly still refers to the first
loop variable within the second loop body.

Fixes: d0267da61489 ("virtio-blk: Configure all host notifiers in a single MR transaction")
Signed-off-by: Mark Mielke <mark.mielke@gmail.com>
Message-id: CALm7yL08qarOu0dnQkTN+pa=BSRC92g31YpQQNDeAiT4yLZWQQ@mail.gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>