reverts r110488

reverts r110488

Breaks maintenance/rebuildFileCache.php with stack trace saying that
FauxRequest::getRequestURL() not implemented

Backtrace:
#0 includes/WebRequest.php(1261): FauxRequest->notImplemented('FauxRequest::ge...')
#1 includes/debug/Debug.php(266): FauxRequest->getRequestURL()
#2 includes/Skin.php(561): MWDebug::getDebugHTML(Object(RequestContext))
#3 includes/SkinTemplate.php(461): Skin->generateDebugHTML()
#4 includes/OutputPage.php(1982): SkinTemplate->outputPage()
#5 maintenance/rebuildFileCache.php(119): OutputPage->output()
#6 maintenance/doMaintenance.php(105): RebuildFileCache->execute()
#7 maintenance/rebuildFileCache.php(146): require_once('/srv/trunk/main...')
#8 {main}