perf test: Cleanup daemon if test is interrupted.

perf test: Cleanup daemon if test is interrupted.

Reorder daemon_start and daemon_exit as the trap handler is added in
daemon_start referencing daemon_exit.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20210317005505.2794804-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>