perf tools: Fix cross-endian analysis

Trying to analyze a big endian data file on little endian system fails
with the error:

  0xa9b40 [0x70]: failed to process type: 9

The problem is that header parsing is not done correctly because the
file attributes are not swapped. Make it so. With this patch able to
analyze a sparc64 data file on x86_64.

Signed-off-by: David Ahern <david.ahern@oracle.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1428610546-178789-1-git-send-email-david.ahern@oracle.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/header.c

@@ -2504,8 +2504,11 @@ int perf_session__read_header(struct perf_session *session)
 		if (read_attr(fd, header, &f_attr) < 0)
 			goto out_errno;
 
-		if (header->needs_swap)
+		if (header->needs_swap) {
+			f_attr.ids.size   = bswap_64(f_attr.ids.size);
+			f_attr.ids.offset = bswap_64(f_attr.ids.offset);
 			perf_event__attr_swap(&f_attr.attr);
+		}
 
 		tmp = lseek(fd, 0, SEEK_CUR);
 		evsel = perf_evsel__new(&f_attr.attr);