Don't insist on ansible-vault taking only one filename parameter

Apart from ansible-vault create, every vault subcommand is happy to deal
with multiple filenames, so we can check that there's at least one, and
make create check separately that there aren't any extra.

lib/ansible/cli/vault.py

@@ -64,8 +64,8 @@ class VaultCLI(CLI):
         self.options, self.args = self.parser.parse_args()
         self.display.verbosity = self.options.verbosity
 
-        if len(self.args) == 0 or len(self.args) > 1:
-            raise AnsibleOptionsError("Vault requires a single filename as a parameter")
+        if len(self.args) == 0:
+            raise AnsibleOptionsError("Vault requires at least one filename as a parameter")
 
     def run(self):
 
@@ -84,6 +84,9 @@ class VaultCLI(CLI):
 
     def execute_create(self):
 
+        if len(self.args) > 1:
+            raise AnsibleOptionsError("ansible-vault create can take only one filename argument")
+
         cipher = getattr(self.options, 'cipher', self.CIPHER)
         this_editor = VaultEditor(cipher, self.vault_pass, self.args[0])
         this_editor.create_file()