remove unused error code in vcl

ever since

    commit 920d4463
    Date:   Thu Jun 23 13:13:28 2016 +0200
    loplugin:singlevalfields in vcl(part1)

Change-Id: I3691d03dadff10585a119ca8db8aa193b5a01702
Reviewed-on: https://gerrit.libreoffice.org/41492Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

include/vcl/graphicfilter.hxx

@@ -41,7 +41,6 @@ struct ConvertData;
 #define ERRCODE_GRFILTER_FORMATERROR  ErrCode(ErrCodeArea::Vcl, ERRCODE_CLASS_GENERAL | 3)
 #define ERRCODE_GRFILTER_VERSIONERROR ErrCode(ErrCodeArea::Vcl, ERRCODE_CLASS_GENERAL | 4)
 #define ERRCODE_GRFILTER_FILTERERROR  ErrCode(ErrCodeArea::Vcl, ERRCODE_CLASS_GENERAL | 5)
-#define ERRCODE_GRFILTER_ABORT        ErrCode(ErrCodeArea::Vcl, ERRCODE_CLASS_GENERAL | 6)
 #define ERRCODE_GRFILTER_TOOBIG       ErrCode(ErrCodeArea::Vcl, ERRCODE_CLASS_GENERAL | 7)
 
 #define GRFILTER_OUTHINT_GREY       1

vcl/source/filter/graphicfilter.cxx

@@ -2449,8 +2449,6 @@ ErrCode GraphicFilter::LoadGraphic( const OUString &rPath, const OUString &rFilt
             aReturnString="version error";
     else if (nRes == ERRCODE_GRFILTER_FILTERERROR)
             aReturnString="filter error";
-    else if (nRes == ERRCODE_GRFILTER_ABORT)
-            aReturnString="import aborted";
     else if (nRes == ERRCODE_GRFILTER_TOOBIG)
             aReturnString="graphic is too big";