perf probe: Fix segfault

Fix segfault in perf probe due to a bug introduced by commit d8639f06
(perf tools: Stop using 'self' in strlist).

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20130312090217.GC4668@in.ibm.com


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