Bahrain activists vow "days of rage" for Grand Prix

* Human rights crisis not over, says Amnesty * Dozens still held in jails * Ecclestone: Bahrain is quiet and peaceful DUBAI, April 18 (Reuters) – Anti-government protesters inBahrain are planning "days of rage" directed at this weekend'sFormula One Grand Prix, while security forces have rounded updozens of activists in a clampdown on the opposition in the GulfArab nation. Bahrain has been in …