[core] range chk http_chunk_append_file_ref_range
[core] range chk http_chunk_append_file_ref_range

add range sanity check in http_chunk_append_file_ref_range()
(before potentially sending HTTP/1.1 chunked header)

gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,lighttpd/lighttpd1.4,lighttpd/lighttpd1.4