[FIX] need_action: avoid reloading needaction counters when there is no menu
[FIX] need_action: avoid reloading needaction counters when there is no menu

- guard do_load_needaction to prevent exceptions when
  there is no menu to load
- avoid calling do_load_needaction where there is no
  menu to reload in the first place

akretion/openerp-web,akretion/openerp-web,akretion/openerp-web