Remove reference/purging_banning, since all info is now in tutorial/purging

Submitted by:	Nils Goroll

crashing child to do so, and then explicitly start it again.

avoid fixed sleeps waiting for the child process to start.

1 thread is a bit on the low side, make the default on RPM based
distros 50.

instead of asserting.

Inspired by:	Patch from DocWilco

fd's early in the case of a timeout.

Fixes	#1023

Conflicts:

	bin/varnishd/cache_waiter_poll.c

Reverting 6 commits seems like more confusion. This is varnishncsa.c from d18336e5.

Note that error wasn't actually working in vcl_deliver, and this just puts
VCC in line with the rest of Varnish. Syntax errors are better than assert
errors.

Re #1027

I'll leave it for later discussion to see if we close #1027, which is
technically a feature request now, though a request for a feature we used
to have (not sure how well it worked).

As per documentation, the ban lurker sleeps ban_lurker_sleep when it is
successful, but on failure it should only sleep 1.0s. No point hammering
the ban list every 0.01s if bans aren't even used.

Fixes #1030

Conflicts:

	bin/varnishd/cache_ban.c

The http_PutProtocol() and http_PutResponse() would in the case of
workspace overflow leave the headers as NULL and log a
SLT_LostHeader. This would make Varnish assert correctly later when
writing to the wire, as these are mandated by HTTP.

This commit changes them to set the fields to static strings instead
("HTTP/1.1" and "Lost Response") when failing to write them to the
workspace. This leaves enough information to complete the protocol in the
case of overflow.

The patch also increases the synthetic object's workspace from static
1024 to param->http_resp_size. This leaves more (and configurable)
room for manipulating the headers of the synthetic object in
vcl_error.

This whole thing has been a collaboration between Martin and myself. I'll
leave it a mystery who wrote what line of code, which part of the comment
and contributed what to the test-case.

In all fairness, it's not a prefect solution, but a far step closer to one.
So it sort of, kinda, more or less, for now, until we get a better
solution:

Fixes: #1031

Conflicts:

	bin/varnishd/cache_http.c

Submitted by:	Nils Goroll

Submitted by:	Nils Goroll

Fixes #1032

Submitted by:	Nils Goroll

Conflicts:

	bin/varnishd/mgt_sandbox_solaris.c