Allow EPIPE in VTCP_Check()
Allow EPIPE in VTCP_Check()

We may see it after a write on a socket which has been closed by
the remote end.

Fixes #2267

feld/Varnish-Cache,feld/Varnish-Cache,feld/Varnish-Cache,feld/Varnish-Cache,feld/Varnish-Cache,gquintard/Varnish-Cache,gquintard/Varnish-Cache,gquintard/Varnish-Cache,gquintard/Varnish-Cache