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##### SUMMARY
If you don't have an ssh client installed in container image or on your system, ansible just throws following error -  `The error was: FileNotFoundError: [Errno 2] No such file or directory: b'ssh': b'ssh'` error. 

```
TASK [Gathering Facts] *********************************************************
[WARNING]: Unhandled error in Python interpreter discovery for host <hostname1>: [Errno 2] No such file or directory: b'ssh': b'ssh'

[WARNING]: Unhandled error in Python interpreter discovery for host <hostname2>: [Errno 2] No such file or directory: b'ssh': b'ssh'

An exception occurred during task execution. To see the full traceback, use -vvv. The error was: FileNotFoundError: [Errno 2] No such file or directory: b'ssh': b'ssh'
fatal: [<hostname1>]: FAILED! => {"msg": "Unexpected failure during module execution.", "stdout": ""}

An exception occurred during task execution. To see the full traceback, use -vvv. The error was: FileNotFoundError: [Errno 2] No such file or directory: b'ssh': b'ssh'
fatal: [<hostname2>]: FAILED! => {"msg": "Unexpected failure during module execution.", "stdout": ""}
```

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
2.9.6
```

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->
Run playbook on the system where ssh client is not installed & playbook is expecting to use ssh keys for remote hosts.


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##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
If possible adding an error message indicating `ssh client is not installed on the system`

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->

<!--- Paste verbatim command output between quotes -->
```paste below
Error message mentioned in the summary 
The error was: FileNotFoundError: [Errno 2] No such file or directory: b'ssh': b'ssh'
```

Thank you!!
if self._play_context.port is not None:
            b_args = (b"-o", b"Port=" + to_bytes(self._play_context.port, nonstring='simplerepr', errors='surrogate_or_strict'))
            self._add_args(b_command, b_args, u"ANSIBLE_REMOTE_PORT/remote_port/ansible_port set")
        key = self._play_context.private_key_file
        if key:
            b_args = (b"-o", b'IdentityFile="' + to_bytes(os.path.expanduser(key), errors='surrogate_or_strict') + b'"')
            self._add_args(b_command, b_args, u"ANSIBLE_PRIVATE_KEY_FILE/private_key_file/ansible_ssh_private_key_file set")
        if not conn_password:
            self._add_args(
                b_command, (
                    b"-o", b"KbdInteractiveAuthentication=no",
                    b"-o", b"PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey",
                    b"-o", b"PasswordAuthentication=no"
                ),
                u"ansible_password/ansible_ssh_password not set"
            )
        user = self._play_context.remote_user
        if user:
            self._add_args(
                b_command,
                (b"-o", b'User="%s"' % to_bytes(self._play_context.remote_user, errors='surrogate_or_strict')),
                u"ANSIBLE_REMOTE_USER/remote_user/ansible_user/user/-u set"
            )
        self._add_args(
            b_command,
            (b"-o", b"ConnectTimeout=" + to_bytes(self._play_context.timeout, errors='surrogate_or_strict', nonstring='simplerepr')),
            u"ANSIBLE_TIMEOUT/timeout set"
        )