perf tools: Make test use the preset debugfs path

Use preset debugfs path instead of hardcoded one.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: acme@redhat.com
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
Link: http://lkml.kernel.org/r/1310635534-4013-4-git-send-email-jolsa@redhat.com


Signed-off-by: Ingo Molnar <mingo@elte.hu>