initial import of __virtual__ log check

[mchugh19]

Attempts to address issues:
saltstack/salt#49935
#2
vmware-archive/salt-testing#34

For test:

# -*- coding: utf-8 -*-
'''
some broken lint test
'''

# Import Python libs
from __future__ import absolute_import, unicode_literals, print_function
import logging

log = logging.getLogger(__name__)

__virtualname__ = 'broken'


def __virtual__():
    '''
    Check dependencies - may be useful in future
    '''

    log.error('not allowed')

    log.debug("some text")
    return __virtualname__

Results in:

pylint salt/modules/ --load-plugins=saltpylint.custom --rcfile=.testing.pylintrc  --disable=all --enable=log-in-virtual
  RuntimeWarning
************* Module salt.modules.broken
salt/modules/broken.py:20: [E1401(log-in-virtual), __virtual__] Log statement detected inside __virtual__ function. Remove it.
salt/modules/broken.py:22: [E1401(log-in-virtual), __virtual__] Log statement detected inside __virtual__ function. Remove it.

@gtmanfred @s0undt3ch