Log Message:
Updated to 2.1.5, provided by Matthew Sporleder in PR 44520.
Summary of changes from 2.1.4 to 2.1.5

  * Two bugs relating to Content-Length and possible duplication of \ 
Content-Length headers have been resolved.
  * Support for bourne-like "here"-documents in the command line \ 
interface, allowing <<__EOF__ and similar schemes.
  * Fixed an issue with re-using connections after Chunked-Encoding.
  * Fix a bug that would inflate the "lost header" count and could \ 
cause problems during heavy traffic over a single connection, typically seen by \ 
load testing.
  * Use the time of cache-insertion for "If-Modified-Since" requests \ 
if a "Last-Modified" header isn't provided by the backend.
  * Merge multi-line Vary and Cache-Control headers from clients, which Google \ 
Chromium seem to split up.
  * Various build fixes and documentation improvements
  * Various bug fixes.