bluetooth autotest: Fix missing argument to log

BUG=None
TEST=Ran local test

Change-Id: I5157613c3a58ea9b45ac0b2054d74015081dba7c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/2001647
Tested-by: Shijin Abraham <shijinabraham@google.com>
Commit-Queue: Shijin Abraham <shijinabraham@google.com>
Auto-Submit: Shijin Abraham <shijinabraham@google.com>
Reviewed-by: Daniel Winkler <danielwinkler@google.com>
diff --git a/server/cros/bluetooth/bluetooth_device.py b/server/cros/bluetooth/bluetooth_device.py
index c85f914..97f1d48 100644
--- a/server/cros/bluetooth/bluetooth_device.py
+++ b/server/cros/bluetooth/bluetooth_device.py
@@ -78,7 +78,7 @@
 
             date =  datetime.strftime(datetime.now(),"%Y:%m:%d %H:%M:%S:%f")
             msg = "bluetooth autotest --- %s : %s ---" % (date, msg)
-            logging.debug("Broadcasting '%s'")
+            logging.debug("Broadcasting '%s'",msg)
 
             if dut:
                 self._proxy.log_message(msg)