Change AddInputFilter and AddOutputFilter to SetInputFilter and

SetOutputFilter.  This corresponds nicely with the other Set
directives, which operate on containers while the Add* directives
tend to work directly on extensions.  [Ryan Bloom]


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@88042 13f79535-47bb-0310-9956-ffa450edef68