fix issue with nested .xhtml includes

fix issue with nested .xhtml includes

This WIP patch fixes an issue where oils_rpt.xhtml fails to
get completely loaded due to an XML parsing error thrown
by mod_xmlent.

The problem appears to be that oils_rpt_param_editor.xhtml
gets included via mod_include and processed by mod_xmlent...
in the context of an overall chain of mod_include and mod_xmlent
that is filtering the overall request for oils_rpt.xhtml.

However, if the same Apache backend processes both the main
request and a sub-request to fetch the included file, the
fact that the Expat parser is shared by all invocations of
mod_xmlent for a given Apache backend is somehow leading
to chunks of oils_rpt.xhtml and the files it's bringing
via mod_include getting processed out of order.

Renaming oils_rpt_param_editor.xhtml to /oils_rpt_param_editor.txt
means that the sub-request to include that file does _not_
pass it through mod_xmlent, avoiding this problem.

Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>