Make an executive decision, and change the regsub() replacement specifiers to
get something which is consistent and nontroubling for URL and query strings.

Since $ and & both are heavily used in query strings, we (DES & I)
have chosen to use \0 ... \9 for replacement indicators, with \0
being the "all matched text" replacement and \1...\9 replacing
with tne N'th paranthesized subexpressions.

   regsub("_barf_", "(b)(a)(r)(f)", "\0\4\3\2\\p") -> "_barffra\p_"




git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@2741 d4fa192b-c00b-0410-8231-f00ffab90ce4