core_input_filter: Stop leaking a brigade by moving buckets to an existing...

core_input_filter: Stop leaking a brigade by moving buckets to an existing brigade instead of calling brigade_split.

PR: 33382
Reviewed By: Justin Erenkrantz, Jeff Trawick


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.0.x@155391 13f79535-47bb-0310-9956-ffa450edef68