coverity#1371125 Copy-paste error

this went wrong with

commit 9b9e5cfd2fa629b2e1dc4a193e48a4a4e8d34126
Date:   Mon Jun 20 17:40:13 2016 +0300

    tdf#99589 - tolower / toupper - dangerous to Turks ...

restore the logic to the original logic, but with the new
api

Change-Id: I445064b19eeefabbd25849bae9ca569710cdfac5
diff --git a/sdext/source/pdfimport/wrapper/wrapper.cxx b/sdext/source/pdfimport/wrapper/wrapper.cxx
index e15ba17..b213e8e 100644
--- a/sdext/source/pdfimport/wrapper/wrapper.cxx
+++ b/sdext/source/pdfimport/wrapper/wrapper.cxx
@@ -471,9 +471,12 @@ sal_Int32 Parser::parseFontCheckForString(
    if (nCopyLen < nAttribLen)
        return 0;
    for (sal_Int32 i = 0; i < nAttribLen; ++i)
        if (rtl::toAsciiLowerCase(pCopy[i]) != rtl::toAsciiLowerCase(pAttrib[i])
            && rtl::toAsciiUpperCase(pCopy[i]) != rtl::toAsciiLowerCase(pAttrib[i]))
    {
        sal_uInt32 nCode = pAttrib[i];
        if (rtl::toAsciiLowerCase(pCopy[i]) != nCode
            && rtl::toAsciiUpperCase(pCopy[i]) != nCode)
            return 0;
    }
    rResult.isItalic |= bItalic;
    rResult.isBold |= bBold;
    return nAttribLen;