http.manage: Try to reuse a previously-input passphrase before asking.

caucase/http.py

@@ -1013,6 +1013,7 @@ def manage(argv=None, stdout=sys.stdout):
     import_ca_dict = defaultdict(
       (lambda: {'crt': None, 'key': None, 'from': []}),
     )
+    password = b''
     for import_ca_path in args.import_ca:
       with open(import_ca_path, 'rb') as ca_file:
         ca_data = ca_file.read()
@@ -1025,7 +1026,6 @@ def manage(argv=None, stdout=sys.stdout):
             _cryptography_backend,
           )
         elif isinstance(component, pem.Key):
-          password = None
           while True:
             component_name = 'key'
             try: