perf tests attr: Fix no-delay test

Following commit:
  commit 509051ea ("perf record: Rename --no-delay to --no-buffering")

removed '-D' option and renamed --no-delay into --no-buffering.
Fixing that in the attr tests.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Richter <tmricht@linux.vnet.ibm.com>
Fixes: 509051ea ("perf record: Rename --no-delay to --no-buffering")
Link: http://lkml.kernel.org/r/20170703145030.12903-9-jolsa@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>