mod_dumpio: Fix for correct dumping of traffic on EBCDIC hosts

Data had been incorrectly converted twice, resulting in
garbled log output.
Based on trunk commit http://svn.apache.org/viewvc?rev=570753&view=rev


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@571398 13f79535-47bb-0310-9956-ffa450edef68