drop dependency on curl/types.h which we were picking up from system 

DQMServices/XdaqCollector/interface/XmasToDQM.h  includes curl/types.h which is 
 - empty file on slc5
 - does not exist for slc6 curl distribution of cms
53X slc6 IBs/releases were working as this file was picked up from system curl. dropping this should not harm as this file is empty anyway.