perf timechart: Fix off-by-one error in 'record' argv handling

Since 367b3152

 (perf timechart: Add support for -P and -T in timechart
recording, 2013-11-01), the 'perf timechart record' command stopped
working:

  $ perf timechart record -- git status
  Workload failed: No such file or directory

This happens because of an off-by-one error while preparing the argv for
cmd_record(): it attempts to execute the command 'status' and complains
that it doesn't exist. Fix this error.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Acked-by: Stanislav Fomichev <stfomichev@yandex-team.ru>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stanislav Fomichev <stfomichev@yandex-team.ru>
Link: http://lkml.kernel.org/r/1394985965-2332-1-git-send-email-artagnon@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>