#1338 OpenXmlFilter has doggy code that has never executed

[Hiroshi Miura]

OpenXmlFilter is internal filter of the MsOfficeFilter. xlsx and docx files are zipped files that packes resources and OpenXml XML files. MsOfficeFilter unzip and OpenXmlFilter read XML file.

In the sequence, no caller callsOpenXmlFilter#isSupportedFile and field flag doCompactTags does not set true. This causes a result that OpenXmlFilter#compactTags is never run.
It does not nothing, so the removal does not effect anything.

This issue is created to backup the PR#2293 review discussion.