Minor fixes for runtime CLI:
Minor fixes for runtime CLI:

  * fix completion for table_show_actions
  * add input sanity-check for table_show_actions and table_info

fixes #344

hanw/behavioral-model,hanw/behavioral-model,hanw/behavioral-model,p4lang/behavioral-model,hanw/behavioral-model,p4lang/behavioral-model,p4lang/behavioral-model,p4lang/behavioral-model,p4lang/behavioral-model,hanw/behavioral-model