Ref #2932

Fixes #2817

The FreeBSD origin has moved into territory where we will not go
(CAPSICUM) so we can now varnish-ify this without cost.

Not yet much of a semantic test, but improving code coverage

Ref #2896

it is on my debian buster

Ref #2817

Ref #2817

Ref #2817

I broke the Y from the X/Y column in 8d47bfc8

Ref #2896

interface-meister @slimhazard tells me the JSONista want objects

Ref #2896

Ref #2896

Ref #2896

Ref #2896

Whenever we gather health information about our backends, we should also
update the other metrics:

	- director changed time
	- total weight
	- number of healthy backends (added)

This also adds back sensible use of (struct vdir).total_weight, which
was maintained by add_backend / remove_backend, but not used anywhere
and useless anyway because, for the hash and random directors, the total
weight of the _healthy_ directors is required.

This also fixes the weight output for backend.list to be relative to the
healthy backends.

Ref #2896

... and name it appropriately

Fixes: #2930

Ref #2896

Ref #2896

include coffee.vcl

Noticed for #2929: travis make check failed, but there is no information
as to why, because that is hidden in the test-suite log

Based on patch from @haproxyFred

towards our max-session limit, and by adjusting the counts
at frame rx/tx time.

Fixes: #2923

Thanks to: xcir

Add another column for the probe result

Ref #2896

backend.list now shows "probe" only if a probe is present.

Ref #2896

The sick state of the director and the healthy callback are the same
thing coming from different directions: Either we query the status
dynamically or we already have it.

For layering directors, the health state is determined by their
backends, so having a director-layer sick state does not make much sense
and duplicates logic.

Also, the sick field duplicates admin_health to some extend (see
cache_director.c do_set_health).

This is also relevant in the context of streamlining the backend.list
output: admin_health "probe" only makes sense if backends actually do
have a probe (= some dynamically determined health state). It appears
streaight forward that the presense of a vdi_healthy_f callback is the
signal for dynamically determined health state.

So we move the sick field into VBE and retire VRT_SetHealth().

We also remove the ctx argument from VRT_SetChanged() because I
previously overlooked that it is required, for example, in probe code
where we got no ctx.

Ref #2896