perf stat: Create events as disabled

perf stat: Create events as disabled

Currently we have 2 kinds of stat counters based on when the event is
enabled:

  1) tracee command events, which are enable once the
     tracee executes exec syscall (enable_on_exec bit)
  2) all other events which get alive within the
     perf_event_open syscall

And 2) case could raise a problem in case we want additional filter to
be attached for event. In this case we want the event to be enabled
after it's configured with filter.

Changing the behaviour of 2) events, so they all are created as disabled
(disabled bit). Adding extra enable call to make them alive once they
finish setup.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1449133606-14429-6-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>