Removed unnecessary field from tw_event.
Removed unnecessary field from tw_event.

JohnPJenkins/ROSS,JohnPJenkins/ROSS,laprej/ROSS-CXX,carothersc/ROSS,JohnPJenkins/ROSS,carothersc/ROSS,laprej/ROSS-CXX,carothersc/ROSS,laprej/ROSS-CXX