add a more verbose log line at the end of cot verification

Author: escapewindow

scriptworker/cot/verify.py

@@ -2222,7 +2222,11 @@ async def verify_chain_of_trust(chain):
                 raise
             else:
                 raise CoTError(str(exc))
-        log.info("Good.")
+        log.info(
+            "Chain {} taskId {} passes chain of trust verification.".format(
+                chain.name, chain.task_id
+            )
+        )
 
 
 # verify_cot_cmdln {{{1