scripts/bloat-o-meter: fix SIGPIPE

scripts/bloat-o-meter: fix SIGPIPE

Fix piping output to a program which quickly exits (read: head -n1)

	$ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux | head -n1
	add/remove: 0/0 grow/shrink: 9/60 up/down: 124/-305 (-181)
	close failed in file object destructor:
	sys.excepthook is missing
	lost sys.stderr

Link: http://lkml.kernel.org/r/20161028204618.GA29923@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>