Fixing usage for different cases

[preved911]

I get different exceptions:

1. if I try to give access_token instead login_or_token:

   $ github-backup access_token dir_name --organization org_name --mirror
   Traceback (most recent call last):
   File "/home/q/Downloads/sputnik_work/github.com/./env/bin/github-backup", line 11, in <module>
   load_entry_point('GitHub-Backup==0.1', 'console_scripts', 'github-backup')()
   File "/home/q/Downloads/sputnik_work/github.com/env/lib/python3.9/site-packages/github_backup/github_backup.py", line 108, in main
   account = gh.get_organization(args.login_or_token)
   File "/home/q/Downloads/sputnik_work/github.com/env/lib/python3.9/site-packages/github/MainClass.py", line 296, in get_organization
   headers, data = self.__requester.requestJsonAndCheck("GET", f"/orgs/{login}")
   File "/home/q/Downloads/sputnik_work/github.com/env/lib/python3.9/site-packages/github/Requester.py", line 353, in requestJsonAndCheck
   return self.__check(
   File "/home/q/Downloads/sputnik_work/github.com/env/lib/python3.9/site-packages/github/Requester.py", line 378, in __check
   raise self.__createException(status, responseHeaders, output)
   github.GithubException.UnknownObjectException: 404 {"message": "Not Found", "documentation_url": "https://docs.github.com/rest/reference/orgs#get-an-organization"}

2. if I try to give access_token as password:

   $ github-backup org_name dir_name --organization org_name --password
   Enter password for org_name:
   Traceback (most recent call last):
   File "/home/q/Downloads/sputnik_work/github.com/./env/bin/github-backup", line 11, in <module>
   load_entry_point('GitHub-Backup==0.1', 'console_scripts', 'github-backup')()
   File "/home/q/Downloads/sputnik_work/github.com/env/lib/python3.9/site-packages/github_backup/github_backup.py", line 118, in main
   assert not (bool(config.get('password', None)) ^ IS_AUTHORIZED), account
   AssertionError: Organization(login="org_name")

   This PR should to fix this behaviour.

[preved911]

--git flag params processing also fixed