impossible to use keyring.core.init_backend(limit=keyring.core.recommended)

[ddstreet]

Describe the bug
This documentation is in the CHANGES.rst file, but it's impossible to use because it results in endless recursion between chainer.py's priority property and backends function.

To Reproduce
Steps to reproduce the behavior:

import keyring
keyring.core.init_backend(keyring.core.recommended)

Traceback (most recent call last):
File "", line 1, in
File "/build/repos/python-keyring/python-keyring/keyring/core.py", line 94, in init_backend
or max(
File "/build/repos/python-keyring/python-keyring/keyring/core.py", line 78, in recommended
return backend.priority >= 1
File "/build/repos/python-keyring/python-keyring/keyring/util/properties.py", line 26, in get
return self.fget.get(None, owner)()
File "/build/repos/python-keyring/python-keyring/keyring/backends/chainer.py", line 26, in priority
return 10 * (len(cls.backends) > 1)
File "/build/repos/python-keyring/python-keyring/keyring/util/properties.py", line 26, in get
return self.fget.get(None, owner)()
File "/build/repos/python-keyring/python-keyring/keyring/backends/chainer.py", line 39, in backends
return sorted(allowed, key=backend.by_priority, reverse=True)
File "/build/repos/python-keyring/python-keyring/keyring/backends/chainer.py", line 34, in
allowed = (
File "/build/repos/python-keyring/python-keyring/keyring/core.py", line 78, in recommended
return backend.priority >= 1

etc...

Expected behavior
restrict backends to only those 'recommended' (priority > 1)

[jaraco]

After creating a test, I'm able to replicate the failure in the test suite. Here's the output:

>       keyring.core.init_backend(keyring.core.recommended)

tests/test_core.py:9: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
keyring/core.py:94: in init_backend
    or max(
keyring/core.py:78: in recommended
    return backend.priority >= 1
keyring/util/properties.py:26: in __get__
    return self.fget.__get__(None, owner)()
keyring/backends/chainer.py:29: in priority
    return 10 if len(cls.backends) > 1 else (fail.Keyring.priority - 1)
keyring/util/properties.py:26: in __get__
    return self.fget.__get__(None, owner)()
keyring/backends/chainer.py:42: in backends
    return sorted(allowed, key=backend.by_priority, reverse=True)
keyring/backends/chainer.py:37: in <genexpr>
    allowed = (
keyring/core.py:78: in recommended
    return backend.priority >= 1
E   RecursionError: maximum recursion depth exceeded while calling a Python object