core, modules: like r1657897 but for core and other modules than mod_proxy.

core, modules: like r1657897 but for core and other modules than mod_proxy.

More uses of ap_map_http_request_error() and AP_FILTER_ERROR so that we never
return an HTTP error status from a handler if some filter generated a response
already.

That is, from a handler, either ap_get_brigade() (an input filter) returned
AP_FILTER_ERROR and we must forward it to ap_die(), or ap_pass_brigade() (an
output filter) failed with any status and we must return AP_FILTER_ERROR in
any case for ap_die() to determine whether a response is needed or not.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1665625 13f79535-47bb-0310-9956-ffa450edef68