don't try to place a header field in error-notes if ap_rgetline()

don't try to place a header field in error-notes if ap_rgetline()
returned something like APR_EOF, since len is not set in this
case and we can go off the end of storage

make sure we set r->status to something when we bail out due
to an error; otherwise, the request goes forward with meaningless
headers

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@93294 13f79535-47bb-0310-9956-ffa450edef68