'Verifies if the requested URL permits a HEAD request.
This was saved inside the KB by the plugin allowed_methods
:return : Sets self._head to the correct value, nothing is returned.'

def _verify_head_enabled(self, url):

    allowed_methods_infos = kb.kb.get('allowed_methods', 'methods')
    allowed_methods = []
    for info in allowed_methods_infos:
        allowed_methods.extend(info['methods'])
    if ('HEAD' in allowed_methods):
        self._head = True
    else:
        self._head = False
