An evsel may have different cpus and threads than the evlist it is in.

Use it's own cpus and threads, when opening the evsel in 'perf record'.
Signed-off-by: Kan Liang <kan.liang@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/1440138194-17001-1-git-send-email-kan.liang@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>