...00134920 "New option for INDIRECT reference
syntax" and e6ef9f12 "Rename this option to make
it sound more generic" had marked
/org.openoffice.Office.Calc/Formula/Syntax/StringRefAddressSyntax (formerly
IndirectFuncGrammar) as oor:nillable="false", even though it is given no value
in officecfg, and the sole code reading it (SCFORMULAOPT_STRING_REF_SYNTAX case
in ScFormulaCfg ctor, sc/source/core/tool/formulaopt.cxx) is prepared to read a
nil value.

Change-Id: Icab871c821f437cd095280e9af8b0c0c11bbef8f