Keep OUString instance by using local variable to avoid crash.

Crash with GCC 4.8 without the modification.
Temporary fix, should be replaced by OUString copy.

Change-Id: Ieb2437f2ee6b02884aa10f2d03a4223306329cd8
Reviewed-on: https://gerrit.libreoffice.org/3647Reviewed-by: Miklos Vajna <vmiklos@suse.cz>
Tested-by: Miklos Vajna <vmiklos@suse.cz>

sw/source/core/text/itrcrsr.cxx

@@ -1593,7 +1593,8 @@ xub_StrLen SwTxtCursor::GetCrsrOfst( SwPosition *pPos, const Point &rPoint,
             else
                 nOldProp = 0;
             {
-                SwTxtSizeInfo aSizeInf( GetInfo(), rText, nCurrStart );
+                OUString rTextStr = rText;
+                SwTxtSizeInfo aSizeInf( GetInfo(), rTextStr, nCurrStart );
                 ((SwTxtCursor*)this)->SeekAndChg( aSizeInf );
                 SwTxtSlot aDiffTxt( &aSizeInf, ((SwTxtPortion*)pPor), false, false );
                 SwFontSave aSave( aSizeInf, pPor->IsDropPortion() ?