we cannot do the accounting without it in a reasonably fast manner.

Keep track of how many fixed and unfixed objects we have in a segment.

Update the object directory when TTL or BAN pointer changes.

Add a testcase for TTL changes.

Don't walk the storage list when we delete a persistent object, just
decrement the segments object count.




git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@3918 d4fa192b-c00b-0410-8231-f00ffab90ce4