simplify copy

Change-Id: Iec5a960b0a6492b1e4690c31b9c2098248c23cfa
diff --git a/sc/source/core/data/global.cxx b/sc/source/core/data/global.cxx
index 2d439ee..3428997 100644
--- a/sc/source/core/data/global.cxx
+++ b/sc/source/core/data/global.cxx
@@ -831,7 +831,7 @@ void ScGlobal::EraseQuotes( OUString& rString, sal_Unicode cQuote, bool bUnescap
{
    if ( IsQuoted( rString, cQuote ) )
    {
        rString = rString.copy( 0, rString.getLength() - 1 ).copy( 1 );
        rString = rString.copy( 1, rString.getLength() - 1 );
        if (bUnescapeEmbedded)
        {
            sal_Unicode pQ[3];