Port a 1.3 EBCDIC fix to 2.0:

This is a port of my 1.3 patch which allows error response strings to be
translated from ebcdic to ascii.  This bug is triggered by trying to
access a non-existant .gif for example.  The content type starts out
being image/gif but is switched by error processing to text/html.
Without this patch, ap_checkconv() is called too early (before the error
processing), so the ebcdic conversion flag gets turned off and the
eventual "404 Not Found" error response is sent to the browser still in
ebcdic.  Not very pretty.

Submitted by:	Greg Ames
Reviewed by:	Jeff Trawick


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@85040 13f79535-47bb-0310-9956-ffa450edef68