Issue #110 fixes

scapy/packet.py

@@ -46,6 +46,8 @@ class Packet(BasePacket):
         "name",
         # used for sr()
         "_answered",
+        # used when sniffing
+        "direction", "sniffed_on"
     ]
     __metaclass__ = Packet_metaclass
     name = None

scapy/sendrecv.py

@@ -618,7 +618,8 @@ interfaces)
     except KeyboardInterrupt:
         pass
     if opened_socket is None:
-        s.close()
+        for s in sniff_sockets:
+            s.close()
     return plist.PacketList(lst,"Sniffed")