perf tools: Do not show trace command if it's not compiled in

The trace command still appears in help message when you run simple
'perf' command.

It's because the generate-cmdlist.sh does not care about the
HAVE_LIBAUDIT_SUPPORT dependency of trace command and puts it into
generated common_cmds array.

Wrapping trace command under HAVE_LIBAUDIT_SUPPORT dependency, which
will exclude it from common_cmds array if HAVE_LIBAUDIT_SUPPORT is not
set.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Noel Grandin <noelgrandin@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1452158050-28061-8-git-send-email-jolsa@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>