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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!!
selector = selectors.DefaultSelector()
        selector.register(p.stdout, selectors.EVENT_READ)
        selector.register(p.stderr, selectors.EVENT_READ)
        
        
        if states[state] == 'ready_to_send' and in_data:
            self._send_initial_data(stdin, in_data, p)
            state += 1
        try:
            while True:
                poll = p.poll()
                events = selector.select(timeout)
                
                if not events:
                    
                    if state <= states.index('awaiting_escalation'):
                        
                        
                        if poll is not None:
                            break
                        self._terminate_process(p)
                        raise AnsibleError('Timeout (%ds) waiting for privilege escalation prompt: %s' % (timeout, to_native(b_stdout)))
                
                
                for key, event in events:
                    if key.fileobj == p.stdout:
                        b_chunk = p.stdout.read()