Looks unneeded nowaday. Backtrace is correctly appended to HTML output
or CLI output when $wgShowDBErrorBacktrace is true.
Not sure what it was supposed to fix.
* Tweaked filecache fallback in fileCachedPage() to try the raw title param. If the DB is down, we can get most views of titles with colons in them to work this way. Previously, it could fail on an interwiki lookup.
* Rewrote class and split into three classes: a base class, and html cache and a more generic cache to be used later.
* The new classes now use RequestContext.
* Renamed fetchPageText() -> fetchText().
* Split out new saveText() function from saveToFileCache().
* Various other cleanups and fixes.
Also fixed backwards setting of $wgDisableCounters in rebuildFileCache.php.
