Tools: Fix script logging

Fix issue preventing scripts respecting --log_level argument, by adding
a non-default handler. Also, add script name to log output.

Change-Id: I100a5c29276d362dc38cd6c46f472e5991873293
Signed-off-by: Raef Coles <raef.coles@arm.com>
diff --git a/tools/modules/sign_then_encrypt_data.py b/tools/modules/sign_then_encrypt_data.py
index 7af18bb..fa77a82 100644
--- a/tools/modules/sign_then_encrypt_data.py
+++ b/tools/modules/sign_then_encrypt_data.py
@@ -9,7 +9,7 @@
 import argparse
 
 import logging
-logger = logging.getLogger("TF-M")
+logger = logging.getLogger("TF-M.{}".format(__name__))
 
 import arg_utils
 import sign_data
@@ -90,4 +90,5 @@
     parser.add_argument("--log_level", help="log level", required=False, default="ERROR", choices=logging._levelToName.values())
 
     args = parser.parse_args()
-    logger.setLevel(args.log_level)
+    logging.getLogger("TF-M").setLevel(args.log_level)
+    logger.addHandler(logging.StreamHandler())