writerfilter: these can be static in ConversionHelper

Change-Id: I2436a884627c4f9b112086cb7ca1a096093ea3f6

writerfilter/source/dmapper/ConversionHelper.cxx

@@ -147,6 +147,7 @@ void MakeBorderLine( sal_Int32 nLineThickness,   sal_Int32 nLineType,
     rToFill.Color = nLineColor;
 }
 
+namespace {
 void lcl_SwapQuotesInField(OUString &rFmt)
 {
     //Swap unescaped " and ' with ' and "
@@ -172,6 +173,7 @@ bool lcl_IsNotAM(OUString& rFmt, sal_Int32 nPos)
             )
         );
 }
+}
 
 OUString ConvertMSFormatStringToSO(
         const OUString& rFormat, lang::Locale& rLocale, bool bHijri)