Correct the string formatting in a info log message

It should be "%s," not just "%,". The error observed was something
like...

ValueError: unsupported format character ',' (0x2c) at index 91

Closes-Bug: #1764696
Change-Id: I601c8640cec857746c2c17f94116da890f4d65e0
(cherry picked from commit 15e95d9b3c)

mistral/db/v2/sqlalchemy/api.py

@@ -177,7 +177,7 @@ def update_on_match(id, specimen, values, session=None):
     except oslo_sqlalchemy.update_match.NoRowsMatched:
         LOG.info(
             "Can't change state of persistent object "
-            "because it has already been changed. [model_class=%, id=%s, "
+            "because it has already been changed. [model_class=%s, id=%s, "
             "specimen=%s, values=%s]",
             model_class, id, specimen, values
         )

releasenotes/notes/fix-regression-when-logging-58faa35f02cefb34.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    A regression was introduced that caused an error when logging a specific
+    message. The string formatting was broken, which caused the logging to
+    fail.