perf header: Set nr_numa_nodes only when we parsed all the data

Sukadev reported segfault on releasing perf env's numa data. It's due
to nr_numa_nodes being set no matter if the numa data gets parsed
properly. The perf_env__exit crash the on releasing non existed data.

Setting nr_numa_nodes only when data are parsed out properly.

Signed-off-by: Jiri Olsa <[e-mail]>
Reported-by: Sukadev Bhattiprolu <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: http://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/header.c

···
 	if (ph->needs_swap)
 		nr = bswap_32(nr);
 
-	ph->env.nr_numa_nodes = nr;
 	nodes = zalloc(sizeof(*nodes) * nr);
 	if (!nodes)
 		return -ENOMEM;
···
 
 		free(str);
 	}
+	ph->env.nr_numa_nodes = nr;
 	ph->env.numa_nodes = nodes;
 	return 0;