Fix a papi_info.position bug in remove_metric
Fix a papi_info.position bug in remove_metric

Include a new papi.info var (metric_enabled) to track if the metric
was enabled.  This leaves us to simply assign the position in the
order we (re)add the metric to the eventset

edwardt/pcp,aeg-aeg/pcpfans,tjanez/pcp,aeg-aeg/pcpfans,prasincs/pcp,aeg-aeg/pcpfans,andyvand/cygpcpfans,aeg-aeg/pcpfans,tjanez/pcp,andyvand/cygpcpfans,prasincs/pcp,tjanez/pcp,tjanez/pcp,edwardt/pcp,wuliming/pcp,mbaldessari/pcp,tjanez/pcp,wuliming/pcp,aeg-aeg/pcpfans,wuliming/pcp,aeg-aeg/pcpfans,adfernandes/pcp,wuliming/pcp,adfernandes/pcp,wuliming/pcp,mbaldessari/pcp,mbaldessari/pcp,edwardt/pcp,tjanez/pcp,wuliming/pcp,adfernandes/pcp,edwardt/pcp,aeg-aeg/pcpfans,mbaldessari/pcp,prasincs/pcp,edwardt/pcp,andyvand/cygpcpfans,prasincs/pcp,adfernandes/pcp,adfernandes/pcp,mbaldessari/pcp,andyvand/cygpcpfans,adfernandes/pcp,prasincs/pcp,mbaldessari/pcp,edwardt/pcp,wuliming/pcp,tjanez/pcp,andyvand/cygpcpfans,tjanez/pcp,andyvand/cygpcpfans,adfernandes/pcp,edwardt/pcp,edwardt/pcp,prasincs/pcp,andyvand/cygpcpfans,prasincs/pcp,adfernandes/pcp,wuliming/pcp,andyvand/cygpcpfans,prasincs/pcp,aeg-aeg/pcpfans