summarize: Silence superfluous error output

scripts/summarize.py

@@ -79,10 +79,11 @@ def show_failures(summary, log_excerpt=100):
         print('These packages failed to build:')
         print()
         for pkg in failed:
-            print('*', pkg['name'])
+            print(f"* {pkg['name']} ({pkg['drvPath']})")
             print()
-            proc = subprocess.run(['nix', 'log', pkg['drvPath']],
+            proc = subprocess.run(['nix', 'log', '--quiet', pkg['drvPath']],
                                  stdout=subprocess.PIPE,
+                                 stderr=subprocess.DEVNULL,
                                  encoding='UTF-8')
             if proc.returncode != 0:
                 print(f'    Error: Failed to fetch log')