automated: use create_out_dir where appropriate

Change-Id: I10181a7d1ebc53491085d80d67f0cd8f9e43071d
Signed-off-by: Daniel Díaz <daniel.diaz@linaro.org>
diff --git a/automated/linux/nginx-apache-bench/apache-bench.sh b/automated/linux/nginx-apache-bench/apache-bench.sh
index 88752e6..3bdccfc 100755
--- a/automated/linux/nginx-apache-bench/apache-bench.sh
+++ b/automated/linux/nginx-apache-bench/apache-bench.sh
@@ -24,8 +24,7 @@
 done
 
 ! check_root && error_msg "This script must be run as root"
-[ -d "${OUTPUT}" ] && mv "${OUTPUT}" "${OUTPUT}_$(date +%Y%m%d%H%M%S)"
-mkdir -p "${OUTPUT}"
+create_out_dir "${OUTPUT}"
 
 dist_name
 # Install and configure LEMP.