socket_vmnet exit when connection is closed

[nirs]

socket_vmnet handles SIGPIPE by terminating. This seems to happen when connection is closed:

INFO | Initializing vmnet.framework (mode 1001)
INFO | * vmnet_subnet_mask: 255.255.255.0
INFO | * vmnet_mtu: 1500
INFO | * vmnet_end_address: 192.168.105.254
INFO | * vmnet_start_address: 192.168.105.1
INFO | * vmnet_interface_id: 9EF22956-C8DF-4242-8239-150985812E89
INFO | * vmnet_max_packet_size: 1514
INFO | * vmnet_nat66_prefix: fd9b:5a14:ba57:e3d3::
INFO | * vmnet_mac_address: 26:42:48:f0:96:21
INFO | Accepted a connection (fd 5)
INFO | Closing a connection (fd 5)
INFO | Received signal [13] Broken pipe: 13
ERROR| writev: Broken pipe

There is no reason to exit when this happens. I think that SIGPIPE should be ignored, since we get EPIPE when writing to closed connection.

More errors can be seen in #43