net: Remove the deprecated way of dumping network packets

"-net dump" has been marked as deprecated since QEMU v2.10, since it
only works with the deprecated 'vlan' parameter (or hubs). Network
dumping should be done with "-object filter-dump" nowadays instead.
Since nobody complained so far about the deprecation message, let's
finally get rid of "-net dump" now.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

qemu-options.hx

@@ -2009,8 +2009,6 @@ DEF("net", HAS_ARG, QEMU_OPTION_net,
     "                configure or create an on-board (or machine default) NIC and\n"
     "                connect it either to VLAN 'n' or the netdev 'nd' (for pluggable\n"
     "                NICs please use '-device devtype,netdev=nd' instead)\n"
-    "-net dump[,vlan=n][,file=f][,len=n]\n"
-    "                dump traffic on vlan 'n' to file 'f' (max n bytes per packet)\n"
     "-net none       use it alone to have zero network devices. If no -net option\n"
     "                is provided, the default is '-net nic -net user'\n"
     "-net ["
@@ -2458,12 +2456,6 @@ qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,sha
      -device virtio-net-pci,netdev=net0
 @end example
 
-@item -net dump[,vlan=@var{n}][,file=@var{file}][,len=@var{len}]
-Dump network traffic on VLAN @var{n} to file @var{file} (@file{qemu-vlan0.pcap} by default).
-At most @var{len} bytes (64k by default) per packet are stored. The file format is
-libpcap, so it can be analyzed with tools such as tcpdump or Wireshark.
-Note: For devices created with '-netdev', use '-object filter-dump,...' instead.
-
 @item -net none
 Indicate that no network devices should be configured. It is used to
 override the default configuration (@option{-net nic -net user}) which