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.ui

@@ -130,6 +130,13 @@
             </property>
            </widget>
           </item>
+          <item>
+           <widget class="QPushButton" name="resetButton">
+            <property name="text">
+             <string>Reset</string>
+            </property>
+           </widget>
+          </item>
          </layout>
         </item>
         <item>