By Joe Brock and MacDonald Dzirutwe HARARE (Reuters) - Zimbabwe's ruling party will dismiss President Robert Mugabe on Sunday and reinstate Emmerson Mnangagwa, the vice-president he fired, two party sources told Reuters on Saturday, as ecstatic crowds celebrated the expected downfall. Mugabe's 37-year rule has been effectively at an end since the army seized control on Wednesday, confining him to his residence, saying it wanted to target the "criminals" around him. State television said Mugabe would meet military commanders on Sunday, quoting Catholic priest Fidelis Mukonori, who has been mediating in negotiations with the president.