change ap_getline to return the size of the buffer when there's no apparent end

to an input line.  This is more like the 1.3 behavior which should help the
callers recognize this condition.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@91714 13f79535-47bb-0310-9956-ffa450edef68