Sadeke Brooks, Staff Reporter With the Jamaica 50 Secretariat launching its campaign song, On A Mission, persons have been reacting to the song, both negatively and positively. The Orville 'Shaggy' Burrell-produced On A Mission song that is being used by the Jamaica 50 Secretariat as part of their new marketing campaign was launched at Track and Records, St Andrew, on Friday afternoon. While bein…