Utils: Fix FileChooser error marking for directories

Amends  b84c8cf892.

Change-Id: I108110cc682d331947c8eb47f62121ed02cd45f9
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/libs/utils/pathchooser.cpp

@@ -582,7 +582,7 @@ bool PathChooser::validatePath(FancyLineEdit *edit, QString *errorMessage) const
         }
         break;
     case PathChooser::Directory:
-        if (filePath.isDir()) {
+        if (filePath.exists() && !filePath.isDir()) {
             if (errorMessage)
                 *errorMessage = tr("The path \"%1\" is not a directory.").arg(filePath.toUserOutput());
             return false;