BinEditor: Complain about missing file, not empty size
BinEditor: Complain about missing file, not empty size

When trying to open a non-existing file with the binary editor, it would
complain that it couldn't empty files, instead of complaining that the
file does not exist.

Change-Id: I50fc8afb8c59cad211ee68356020a81891708097
Task-number: QTCREATORBUG-14078
Reviewed-by: Christian Stenger <accbb51712d7b9c4fb108439d01e716148e5f9e6@theqtcompany.com>

xianian/qt-creator,xianian/qt-creator,danimo/qt-creator,Distrotech/qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,Distrotech/qtcreator,danimo/qt-creator,Distrotech/qtcreator,martyone/sailfish-qtcreator,danimo/qt-creator,Distrotech/qtcreator,martyone/sailfish-qtcreator,Distrotech/qtcreator,martyone/sailfish-qtcreator,danimo/qt-creator,martyone/sailfish-qtcreator,danimo/qt-creator,xianian/qt-creator,xianian/qt-creator,xianian/qt-creator,danimo/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,Distrotech/qtcreator,martyone/sailfish-qtcreator,danimo/qt-creator,Distrotech/qtcreator,xianian/qt-creator,danimo/qt-creator,xianian/qt-creator,martyone/sailfish-qtcreator,danimo/qt-creator,martyone/sailfish-qtcreator