Initialize the backend, only do so if the fs supports an init function

def init(self, back=None):
        '''
        Initialize the backend, only do so if the fs supports an init function
        '''
        back = self.backends(back)
        for fsb in back:
            fstr = '{0}.init'.format(fsb)
            if fstr in self.servers:
                self.servers[fstr]()