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 <christian.stenger@theqtcompany.com>

src/plugins/bineditor/bineditorplugin.cpp

@@ -267,8 +267,10 @@ public:
 
     bool open(QString *errorString, const QString &fileName, quint64 offset = 0) {
         QFile file(fileName);
+        if (file.open(QIODevice::ReadOnly)) {
+            file.close();
             quint64 size = static_cast<quint64>(file.size());
-        if (size == 0 && !fileName.isEmpty()) {
+            if (size == 0) {
                 QString msg = tr("The Binary Editor cannot open empty files.");
                 if (errorString)
                     *errorString = msg;
@@ -278,8 +280,6 @@ public:
             }
             if (offset >= size)
                 return false;
-        if (file.open(QIODevice::ReadOnly)) {
-            file.close();
             setFilePath(FileName::fromString(fileName));
             m_widget->setSizes(offset, file.size());
             return true;