perf machine: Fix leak of 'struct thread' on error path

__machine__findnew_thread() creates a 'struct thread' but does not free
it on the error path. Fix it.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1405495184-20441-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/machine.c

@@ -370,8 +370,10 @@ static struct thread *__machine__findnew_thread(struct machine *machine,
 		 * within thread__init_map_groups to find the thread
 		 * leader and that would screwed the rb tree.
 		 */
-		if (thread__init_map_groups(th, machine))
+		if (thread__init_map_groups(th, machine)) {
+			thread__delete(th);
 			return NULL;
+		}
 	}
 
 	return th;