revert r1031670:

revert r1031670:

    Change the default of the Header directive to apply to responses of all types
    instead of just 2xx successful responses.

This turned out to be do more harm than good for anything other
than "set", since "always" doesn't ever see/operate on existing
r->headers_out headers -- just err_headers_out.

I think onsuccess needs to remain the default and this needs to move into a
doc revamp.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1053516 13f79535-47bb-0310-9956-ffa450edef68