Ensure that the proper status line is written to the client, fixing

Ensure that the proper status line is written to the client, fixing
incorrect status lines caused by filters which modify r->status without
resetting r->status_line, such as the built-in byterange filter.

Note: For the byterange example, the handler must set r->status_line
even though this is a 200 response.  Some proxy-type modules blindly
set r->status_line as set by the origin server and thus trigger
the problem with byteranges if the origin server didn't handle the
byterange.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@379562 13f79535-47bb-0310-9956-ffa450edef68