Git: Add reset button to branches dialog

Task-number: QTCREATORBUG-11391

Change-Id: I5146a8b00a88124f96c788cba2bbfa786618ee20
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/git/branchdialog.h

@@ -70,6 +70,7 @@ private slots:
     void rename();
     void diff();
     void log();
+    void reset();
     void merge();
     void rebase();
     void cherryPick();