htmlfile should get an assignment not a comparison

Signed-off-by: gregory guy <g-gregory@gmx.fr>
(cherry picked from commit 8bebc3f6f4)

src/knowit.cpp

@@ -964,9 +964,9 @@ void Knowit::slotFileExport()
         htmlfile = htmlfile.left(htmlfile.length() - 4) + ".html";
      else htmlfile = "";
   }
-  if (htmlfile.isEmpty())
-     htmlfile == TQDir::currentDirPath();
-
+  if (htmlfile.isEmpty()) {
+     htmlfile = TQDir::currentDirPath();
+  }
   /* Confirm/choose filename */
   KURL url=KFileDialog::getSaveURL(htmlfile,
         i18n("*.html|HTML files (*.html)\n*|All files"), this, i18n("Export to HTML"));