Use it to hold the derived vary string for the request (if any) and
skip busy objects with non-matching Vary during hash lookup.

Idea by:	sky

memlevel 8.

Fix testcases which depend on older values.

gzip_window and gzip_memlevel.

Still same pessimal values though.

Not detected by:  FlexeLint 9.00f
Detected by:  FlexeLint 9.00g

to prevent old junk on the workspace from being taken for valid.

cache_hash to cache_center.

do not trusting) that all objects under an objhdr have the same
Vary string.

Build a vary string for the request on the wrk->ws as we do the
comparison and use it as a cache for subsequent comparisons.

This will also be first step of sky's "pre-vary"

white space.

Repack struct object, reducing a couple of field widths along the way.

This shaves 16 bytes of struct object.

Fixes: #876

The size of a regex is a size_t.  Spotted by gcc 4.6

returns random file names

Eventually, we want to be able to do synthetic everywhere, but for
now, mark it as just available in vcl_error.

Fixes: #936

Record the original strdup-ed value so we can free it afterwards.

Fixes: #935

We were accidentially sending an end-chunk in some cases where a
response was bodyless such as for 304s.

Thanks to Chris Davies for spotting them.