Vcs/Text search: Remove a few addAutoReleaseObject uses

Using a QObject parent suffices here.

Change-Id: I4dc5448511d55bf14fbd8f810e91336a49e94094
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/git/gitgrep.h

@@ -39,7 +39,7 @@ class GitGrep : public TextEditor::SearchEngine
     Q_DECLARE_TR_FUNCTIONS(GitGrep)
 
 public:
-    GitGrep();
+    explicit GitGrep(QObject *parent);
     ~GitGrep() override;
     QString title() const override;
     QString toolTip() const override;