Translations fixes

Do not translate strings, which should not be translated
Remove unnecessary/unused strings.

src/rss/automatedrssdownloader.ui

@@ -283,7 +283,7 @@
                  <bool>false</bool>
                 </property>
                 <property name="text">
-                 <string>...</string>
+                 <string notr="true">...</string>
                 </property>
                </widget>
               </item>

src/rss/rss_imp.cpp

@@ -206,7 +206,7 @@ void RSSImp::on_newFeedButton_clicked()
     return;
 
   if (m_feedList->hasFeed(newUrl)) {
-    QMessageBox::warning(this, tr("qBittorrent"),
+    QMessageBox::warning(this, "qBittorrent",
                          tr("This rss feed is already in the list."),
                          QMessageBox::Ok);
     return;