Catch fs.opener.errors.UnsupportedProtocol

[jayvdb]

Because of moremoban/gitfs2#7 and moremoban/pypifs#6 , those packages are not yet in openSUSE , but the main moban was upgraded to the latest, and the result when those openers are needed:

> python3 -m moban
Traceback (most recent call last):
  File "/usr/lib64/python3.7/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib64/python3.7/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/usr/lib/python3.7/site-packages/moban/__main__.py", line 4, in <module>
    main()
  File "/usr/lib/python3.7/site-packages/moban/main.py", line 56, in main
    count = handle_moban_file(moban_file, options)
  File "/usr/lib/python3.7/site-packages/moban/main.py", line 191, in handle_moban_file
    mobanfile.handle_moban_file_v1(moban_file_configurations, options)
  File "/usr/lib/python3.7/site-packages/moban/mobanfile/__init__.py", line 62, in handle_moban_file_v1
    merged_options[constants.LABEL_TMPL_DIRS]
  File "/usr/lib/python3.7/site-packages/moban/utils.py", line 29, in verify_the_existence_of_directories
    if file_system.exists(directory):
  File "/usr/lib/python3.7/site-packages/moban/file_system.py", line 36, in wrapper
    return function_in_this_module(*args, **kwds)
  File "/usr/lib/python3.7/site-packages/moban/file_system.py", line 164, in exists
    with fs.open_fs(dir_name) as the_fs:
  File "/usr/lib/python3.7/site-packages/fs/opener/registry.py", line 226, in open_fs
    default_protocol=default_protocol,
  File "/usr/lib/python3.7/site-packages/fs/opener/registry.py", line 185, in open
    opener = self.get_opener(protocol)
  File "/usr/lib/python3.7/site-packages/fs/opener/registry.py", line 128, in get_opener
    "protocol '{}' is not supported".format(protocol)
fs.opener.errors.UnsupportedProtocol: protocol 'git' is not supported

This should be handled more gracefully, and IMO they should be optional dependencies again as moban core doesnt need them.

[chfw]

Yes, agree with you.

Compulsory dependency was introduced when we started 0.6.x, because 0.5.x had all. That why I have listed as a package dependency.

Starting with 0.7.x, Both should be dropped in package requirements.