OdmExtractDAO - fetchItemGroupMetaData - unnecessary sql execution

[toskrip]

In OdmExtraDAO fetchItemGroupMetaData method there is a sql statement that is executed but results are never used and further prior execution of sql the return resultset types are not preset which may result in exception while parsing the results (discovered by accident while printing of some specific CRF (not all) is triggered leading to hanging page).

ArrayList<HashMap<String, Object>> rows = select(this.getItemDataMaxLengths(cvIds));

Note: does not seem to be regression, this sql was also there before refactoring of DAO but it is completely unecessary as results have been directly wiped:

rows.clear();

I am proposing to remove this part because it may produce exceptions also elsewhere.