Check all sources of Content-Encoding in inflate_out filter

PR 42993
Reasoning: http://marc.info/?l=apache-httpd-dev&m=118643107831358&w=2


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@563317 13f79535-47bb-0310-9956-ffa450edef68