Failure to read the right number of bytes (typically due to remote HUP)
would log "straight insufficient bytes", which is the same as we log for
C-L based fetches. Change this to "chunked insufficient bytes". (Assuming
this was a copy-paste error).

Ref #3088

apparently the additional argument was just silently tolerated by
varnishtest

Tests #3088

Using vut->last_sighup was not adequate, because the VUT_Main loop might
have terminated for some other signal or because of EOF.

On the other hand, we do not want to end the curses loop just because
the VUT_Main loop has ended in order to continue to display the last
state (and maybe the EOF in the top right corner).

So while I see that checking just one flag has some beauty to it, I do
think that directly checking the signal counters is both simple and
robust.

Fixes #3088 for varnishtop and varnishhist

Fixes #3088 for varnishstat

note that besides handling SIGHUP, this also adds handling of SIGTERM
and SIGINT, which were also missing.

Refs a791188e

backend None does not actually create a backend, so tests which require
one need to use the bad_ip method.

... for those cases which can easily be changed (most of them).

This avoids issues with failing tests when bad_ip is actually reachable
via tcp on the respective port, as seen for example with b00068.vtc

by properly cleaning up the busyobj

Also move the relevant code from cache_vrt.c to cache_fetch.c

As we fini the director during cleanup, we now also need to handle the
backend connection gone missing in vbf_stp_fetch(). The hypothetical
alternative would be to not fini the director, but I believe this is not
safe in case it also used some workspace.

Fixes #3009

in particular because it may live on the workspace.

Required for #3009

imples the following changes:

* VDI_Finish() is now always conditional on bo->director_state !=
  DIR_S_NULL, making it idempotent

* introduces additional calls to VFP_Close() from startfetch and
  for the filter_list / VCL_StackVFP error in vbf_stp_fetch(),
  but VFP_Close() is idempotent.

* adds VFP_Close() for VFP_Open() failure in vbf_stp_fetch() which
  I think is actually missing (for the case that some VFPs could
  get opened before the open failure)

* calls VDI_Finish() earlier in vbf_stp_fetchend: I checked the
  code and can not see any issue with this.

motivated by #3009

required for #3009

On a network where you can't trust the DNS resolver because it filters
AAAA records out v00016.vtc fails.

... to avoid future regressions of a very useful feature.

Using a gap in the test numbers.

We should avoid the word "received" in the context of response fields,
since we don't "receive" resp.* fields, only beresp. This also fixes
another inconsistency in the manual:

    RespReason - Client response response
        The HTTP response string received.

Ref #3067

@andrewwiik would you please look after the user documentation?

Ref #3067

Ref #3067

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