qemu-sockets: Fix potential memory leak

The old code leaks variable 'peer'.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
(cherry picked from commit 39b38459)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>