Set explicit default for ANSIBLE_SSH_ARGS

The earlier code behaved exactly as though this default had been set,
but it was actually handled as a(n unnecessary) special case inside the
connection plugin, rather than set as an explicit default.

If the default is overriden either in ansible.cfg or the environment,
the new code will continue to work (in fact, it won't know or care,
since it just uses the value set in the PlayContext).

This is submitted as a separate commit for easier review to address
backwards-compatibility concerns.

lib/ansible/constants.py

@@ -224,7 +224,7 @@ RETRY_FILES_SAVE_PATH          = get_config(p, DEFAULTS, 'retry_files_save_path'
 DEFAULT_NULL_REPRESENTATION    = get_config(p, DEFAULTS, 'null_representation', 'ANSIBLE_NULL_REPRESENTATION', None, isnone=True)
 
 # CONNECTION RELATED
-ANSIBLE_SSH_ARGS               = get_config(p, 'ssh_connection', 'ssh_args', 'ANSIBLE_SSH_ARGS', None)
+ANSIBLE_SSH_ARGS               = get_config(p, 'ssh_connection', 'ssh_args', 'ANSIBLE_SSH_ARGS', '-o ControlMaster=auto -o ControlPersist=60s')
 ANSIBLE_SSH_CONTROL_PATH       = get_config(p, 'ssh_connection', 'control_path', 'ANSIBLE_SSH_CONTROL_PATH', "%(directory)s/ansible-ssh-%%h-%%p-%%r")
 ANSIBLE_SSH_PIPELINING         = get_config(p, 'ssh_connection', 'pipelining', 'ANSIBLE_SSH_PIPELINING', False, boolean=True)
 ANSIBLE_SSH_RETRIES            = get_config(p, 'ssh_connection', 'retries', 'ANSIBLE_SSH_RETRIES', 0, integer=True)

lib/ansible/plugins/connection/ssh.py

@@ -150,18 +150,11 @@ class Connection(ConnectionBase):
             # Older versions of ssh (e.g. in RHEL 6) don't accept sftp -q.
             self._command += ['-q']
 
-        # Next, we add [ssh_connection]ssh_args from ansible.cfg, or the default
-        # Control* settings.
+        # Next, we add [ssh_connection]ssh_args from ansible.cfg.
 
         if self._play_context.ssh_args:
             args = self._split_args(self._play_context.ssh_args)
             self._add_args("ansible.cfg set ssh_args", args)
-        else:
-            args = (
-                "-o", "ControlMaster=auto",
-                "-o", "ControlPersist=60s"
-            )
-            self._add_args("default arguments", args)
 
         # Now we add various arguments controlled by configuration file settings
         # (e.g. host_key_checking) or inventory variables (ansible_ssh_port) or