Log Message:
Changes 3.5.22:
* HTTP: MUST ignore a [revalidation] response with an older Date header.
* Optimized/simplified buffering: Appending nothing is always possible.
* Hide OpenSSL tricks from Valgrind far-reaching initialization errors.
* Avoid segfaults when debugging section 4 at level 9.
* Bug 4302 pt2: IPFilter v5 transparent interception
* Bug 4594: build failure with clang 3.9
* Bug 4471: revalidation doesn't work when expired cached object lacks Last-Modified.
* Bug 2833: Collapse internal revalidation requests (SMP-unaware caches)
* Bug 3819: "fd >= 0" assertion in file_write() during reconfiguration
* Do not leak url_rewrite_extras and store_id_extras on reconfigure/shutdown.
* Do reset $HOME if needed after r13435. Minimize putenv() memory leaks.
* Bug 4228: ./configure bug/typo in r14394.
* Fix potential ICAP null pointer dereference after rev.14082
* Fix logged request size (%http::>st) and other size-related %codes.