Parses config file for the OSPF vrf name

           Args:
               config(str):  Running configuration
           Returns:
               dict: key: ospf_vrf (str)

def _parse_vrf(self, config):
        """Parses config file for the OSPF vrf name

           Args:
               config(str):  Running configuration
           Returns:
               dict: key: ospf_vrf (str)
        """
        match = re.search(r'^router ospf \d+ vrf (\w+)', config)
        if match:
            return dict(vrf=match.group(1))
        return dict(vrf='default')