Surpress warning on comparison between signed and unsigned.

Change-Id: Ia155114817e3b28a201f734647b758cf7cebefce
diff --git a/sc/source/core/tool/formulagroup.cxx b/sc/source/core/tool/formulagroup.cxx
index c554e9c..1ee57b5 100644
--- a/sc/source/core/tool/formulagroup.cxx
+++ b/sc/source/core/tool/formulagroup.cxx
@@ -39,7 +39,7 @@ bool FormulaGroupInterpreter::interpret()
                {
                    const formula::SingleVectorRefToken* p2 = static_cast<const formula::SingleVectorRefToken*>(p);
                    const double* pArray = p2->GetArray();
                    aCode2.AddDouble(i < p2->GetArrayLength() ? pArray[i] : 0.0);
                    aCode2.AddDouble(static_cast<size_t>(i) < p2->GetArrayLength() ? pArray[i] : 0.0);
                }
                break;
                case formula::svDoubleVectorRef: