[Qt] fix possibilty to delete last sendcoins entry
[Qt] fix possibilty to delete last sendcoins entry

- hide the entry about to be deleted, and if it is the last entry add a
  new one, so that we always have one entry in our list

domob1812/crowncoin,syscoin/syscoin,domob1812/crowncoin,syscoin/syscoin,domob1812/crowncoin,Infernoman/crowncoin,Infernoman/crowncoin,Infernoman/crowncoin,syscoin/syscoin,Crowndev/crowncoin,syscoin/syscoin,Crowndev/crowncoin,syscoin/syscoin,syscoin/syscoin,Crowndev/crowncoin,Infernoman/crowncoin,domob1812/crowncoin,syscoin/syscoin,domob1812/crowncoin,syscoin/syscoin,Crowndev/crowncoin,Crowndev/crowncoin,Crowndev/crowncoin,domob1812/crowncoin,Infernoman/crowncoin,Infernoman/crowncoin