Powercap component causes fread() failure when called after PAPI_read()/PAPI_accum()

[Heike Jagode]

When PAPI_read() or PAPI_accum() is called between fopen() and fread() then fread() returns an error (reported by Tao Gao, University of Delaware).

We have tested with multiple different components (example, perf_event, perf_event_uncore, powercap). So far, this error only happens when the powercap component is enabled and powercap events are used.

[Heike Jagode]

Issue is resolved after cleaning up careless file handling in the powercap component, such as closing of open files when no longer used, proper setting of open/close flag, etc.