[qa] Avoid printing to console during cache creation

test/functional/test_framework/util.py

@@ -301,6 +301,7 @@ def initialize_datadir(dirname, n):
         f.write("keypool=1\n")
         f.write("discover=0\n")
         f.write("listenonion=0\n")
+        f.write("printtoconsole=0\n")
         os.makedirs(os.path.join(datadir, 'stderr'), exist_ok=True)
         os.makedirs(os.path.join(datadir, 'stdout'), exist_ok=True)
     return datadir