perf tools: Misc small fixes

- util/header.c
	"len" is aligned to 64. So, it tries to write the out of
	long_name buffer.

	So, this use "zero_buf" to write aligned area.

- util/trace-event-read.c
	"size" is not including nul byte. So, this allocates it, and set '\0'.

- util/trace-event-parse.c
	It needs parens to calc correct size.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <87d42s8iiu.fsf_-_@devron.myhome.or.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>