tdf#42982 Add informative message to RuntimeException in OQuery

Change-Id: I8bac7b8b60b89bedcd61c92e8dbb63a8a9f5be21
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/201073
Tested-by: Jenkins
Reviewed-by: Heiko Tietze <heiko.tietze@documentfoundation.org>

dbaccess/source/core/api/query.cxx

@@ -169,7 +169,7 @@ void OQuery::rebuildColumns()
             xColumns = OPrivateColumns::createWithIntrinsicNames(
                 aParseColumns, xDBMeta->supportsMixedCaseQuotedIdentifiers(), *this, m_aMutex ).release();
             if ( !xColumns.is() )
-                throw RuntimeException();
+                throw RuntimeException(u"dbaccess: OQuery::impl_initColumns_nothrow: failed to create columns"_ustr);
         }
 
         const Sequence<OUString> aColNames = xColumns->getElementNames();