Fix spurious init_thread call in threads.c
Fix spurious init_thread call in threads.c

threads.c was calling init_thread() on all components,
even ones that were disabled

Fix it to honor the disable bit, as well as for
shutdown_thread().  This was causing perfctr
disable code to not work.

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