ap_rgetline_core() now pulls from r->proto_input_filters

for better input filtering behavior during chunked trailer
processing by ap_http_filter().
Backports: r1446421
Submitted by: joes



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x-merge-http-strict@1768093 13f79535-47bb-0310-9956-ffa450edef68