avoid shadowing outer config() func in modules.apache._parse_config()

************* Module salt.modules.apache
salt/modules/apache.py:381: [W0621(redefined-outer-name), _parse_config] Redefining name 'config' from outer scope (line 410)
Merge pull request #11291 from hulu/apache-config-shadow

avoid shadowing outer config() func in modules.apache._parse_config()