longparas: none of the callers check for the error case

so we can safely change the return of 0xFFFF to 0 without
changing any callers. Which makes this safe seeing as before
now every caller would have done something stupid with the
results

Change-Id: I10d9f12525de10661ed82f3405e6c728d38be106

sfx2/source/control/thumbnailviewitem.cxx

@@ -323,7 +323,7 @@ void ThumbnailViewItem::addTextPrimitives (const OUString& rText, const Thumbnai
 
     // Create the text primitives
     sal_uInt16 nLineStart = 0;
-    for (sal_uInt16 i=0; i<aTextEngine.GetLineCount(0); ++i)
+    for (sal_uInt16 i=0; i < aTextEngine.GetLineCount(0); ++i)
     {
         sal_uInt16 nLineLength = aTextEngine.GetLineLen(0, i);
         double nLineWidth = aTextDev.getTextWidth (aText, nLineStart, nLineLength);

vcl/source/edit/texteng.cxx

@@ -1260,7 +1260,7 @@ sal_uInt16 TextEngine::GetLineCount( sal_uLong nParagraph ) const
     if ( pPPortion )
         return pPPortion->GetLines().size();
 
-    return 0xFFFF;
+    return 0;
 }
 
 sal_uInt16 TextEngine::GetLineLen( sal_uLong nParagraph, sal_uInt16 nLine ) const
@@ -1274,7 +1274,7 @@ sal_uInt16 TextEngine::GetLineLen( sal_uLong nParagraph, sal_uInt16 nLine ) cons
         return pLine->GetLen();
     }
 
-    return 0xFFFF;
+    return 0;
 }
 
 sal_uLong TextEngine::CalcParaHeight( sal_uLong nParagraph ) const