perf probe: Fix segfault

Fix segfault in perf probe due to a bug introduced by commit d8639f0
(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>

tools/perf/util/strlist.c

@@ -143,7 +143,7 @@ struct strlist *strlist__new(bool dupstr, const char *list)
 		slist->rblist.node_delete = strlist__node_delete;
 
 		slist->dupstr	 = dupstr;
-		if (slist && strlist__parse_list(slist, list) != 0)
+		if (list && strlist__parse_list(slist, list) != 0)
 			goto out_error;
 	}