Fix off-by-one error just introduced for .initial setup.

the .initial setup.

(more precise if a header is set more then once or overwritten).

Fixes #1683

	varnish ${id} -expect !${vsc-identifier}

detailed probing information.

Retire the "debug.health" CLI command.

entire level of indirection in the backend probe code.

VCLs to cold (if they're in "auto" mode).

"auto", "cold" or "warm".

Regularize the names in the generated code.
Pass VCL events to backends.

The VRT side of things still needs attention