add RewriteOptions LongURLOptimization

Variable expansion in RewriteCond causes strings to be duplicated
out of r->pool.  If the variables are long and many conditions
are evaluated, r->pool can get seriously bloated.

Clear the memory used for variable expansion for each set of conditons
once the set of conditions fails to match.




git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1798938 13f79535-47bb-0310-9956-ffa450edef68