slirp: check sscanf result when emulating ident

slirp: check sscanf result when emulating ident

When emulating ident in tcp_emu, if the strchr checks passed but the
sscanf check failed, two uninitialized variables would be copied and
sent in the reply, so move this code inside the if(sscanf()) clause.

Signed-off-by: William Bowling <will@wbowling.info>
Cc: qemu-stable@nongnu.org
Cc: secalert@redhat.com
Message-Id: <1551476756-25749-1-git-send-email-will@wbowling.info>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
(cherry picked from commit d3222975c7d6cda9e25809dea05241188457b113)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>