Fixed a seg fault error, if the PFM device is busy _papi_hwd_shutdown would segfault because of testing of an unitialized variable.
Fixed a seg fault error, if the PFM device is busy _papi_hwd_shutdown
would segfault because of testing of an unitialized variable.

arm-hpc/papi,pyrovski/papi,pyrovski/papi,pyrovski/papi,pyrovski/papi,pyrovski/papi,arm-hpc/papi,arm-hpc/papi,pyrovski/papi,pyrovski/papi,arm-hpc/papi,arm-hpc/papi,pyrovski/papi,arm-hpc/papi,arm-hpc/papi