qemu-iotests: Fix stderr handling in common.qemu

The original intention was to pipe stderr of qemu into $fifo_out.
However, the redirections were specified in the wrong order for this.
This patch fixes it.

Now qemu's output on stderr can be retrieved with _send_qemu_cmd, which
applies several useful filters on the output that were missing before.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Message-id: 1416497234-29880-9-git-send-email-kwolf@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/common.qemu

@@ -153,8 +153,9 @@ function _launch_qemu()
     mkfifo "${fifo_out}"
     mkfifo "${fifo_in}"
 
-    "${QEMU}" -nographic -serial none ${comm} -machine accel=qtest "${@}" 2>&1 \
+    "${QEMU}" -nographic -serial none ${comm} -machine accel=qtest "${@}" \
                                                                 >"${fifo_out}" \
+                                                                2>&1 \
                                                                 <"${fifo_in}" &
     QEMU_PID[${_QEMU_HANDLE}]=$!