At verbose=0, only spit out a single line if a test passes, but dump
the full show if it fails.

Should make "make check" less tedious to read through.

Fix a race situation related to vsb's while shutting down.




git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@4486 d4fa192b-c00b-0410-8231-f00ffab90ce4