SQL string quoting: escape "'" character also at beginning of string

Change-Id: I51db43c1a3b6d3c93a04a3419238ea286cab987e
Reviewed-on: https://gerrit.libreoffice.org/52575Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Lionel Elie Mamane <lionel@mamane.lu>

connectivity/source/commontools/DateConversion.cxx

@@ -80,7 +80,7 @@ OUString DBTypeConversion::toSQLString(sal_Int32 eType, const Any& _rVal,
                     {
                         OUString aTemp;
                         _rxTypeConverter->convertToSimpleType(_rVal, TypeClass_STRING) >>= aTemp;
-                        sal_Int32 nIndex = sal_Int32(-1);
+                        sal_Int32 nIndex = sal_Int32(-2);
                         const OUString sQuot("\'");
                         do
                         {