Sentence:  ... we can't give any one house-room just now, for every Christmas Eve such a pack of Trolls come down upon us that we are forced to <WSD>flit</WSD>, and haven't so much as a house over our own heads, to say nothing of lending one to any one else. 
Meaning of the word marked with <WSD> tags:  To move house (sometimes a sudden move to avoid debts).