perf test: Fixup for the die() removal

The commit 32c7f7383a09 ("perf test: Remove die() calls") replaced die()
call to pr_debug + return -1, but it should be pr_err otherwise it'll
not show up unless -v option is given.  Fix it.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1347415866-303-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>