Git: Save all documents before stash pop

... and refresh the stash dialog

Change-Id: Iba16efc4f612cd1997493206704100ec57493932
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/git/gitplugin.h

@@ -127,6 +127,7 @@ private slots:
     void startFixupCommit();
     void stash();
     void stashSnapshot();
+    void stashPop();
     void branchList();
     void remoteList();
     void stashList();