<!--- Verify first that your feature was not already discussed on GitHub -->
<!--- Complete *all* sections as described, this form is processed automatically -->

##### SUMMARY
<!--- Describe the new feature/improvement briefly below -->
The `ssh_opts` parameter relies on setting environment variables for git, such as GIT_SSH. Git did not recognize this environment variable until version 2.3.0 (see https://git-scm.com/docs/git/2.3.0), and many contemporary OSes (RHEL 7, CentOS7) include older versions of Git (1.8.3.1).

It would be useful to provide a warning in this case, similar to the warning for the `depth` parameter. E.g. "Your git version is too old to support the ssh_opts argument."

##### ISSUE TYPE
- Feature Idea

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

##### ADDITIONAL INFORMATION
<!--- Describe how the feature would be used, why it is needed and what it would solve -->
It would save users time when trying to troubleshoot failed git connections via SSH.

<!--- Paste example playbooks or commands between quotes below -->
```yaml
- name: clone a git repo
  git:
    repo: git@github.com:cherdt/hello_ansible.git
    dest: /opt/hello_ansible
    version: master
    ssh_opts: "{{-o IdentityFile=github_id_rsa}}"
```

<!--- HINT: You can also paste gist.github.com links for larger files -->

""" Helper function for creating archive using git_archive """
    all_archive_fmt = {'.zip': 'zip', '.gz': 'tar.gz', '.tar': 'tar',
                       '.tgz': 'tgz'}
    _, archive_ext = os.path.splitext(archive)
    archive_fmt = all_archive_fmt.get(archive_ext, None)
    if archive_fmt is None:
        module.fail_json(msg="Unable to get file extension from "
                             "archive file name : %s" % archive,
                         details="Please specify archive as filename with "
                                 "extension. File extension can be one "
                                 "of ['tar', 'tar.gz', 'zip', 'tgz']")
    repo_name = repo.split("/")[-1].replace(".git", "")
    if os.path.exists(archive):
        
        
        
        tempdir = tempfile.mkdtemp()
        new_archive_dest = os.path.join(tempdir, repo_name)
        new_archive = new_archive_dest + '.' + archive_fmt
        git_archive(git_path, module, dest, new_archive, archive_fmt, archive_prefix, version)
        
        if filecmp.cmp(new_archive, archive):