Here is the version, accurate and verbatim, from "The Gathering". As was said, it was attributed to Kipling. It does, after all, have a Kipling flair and feel, and I'm thinking that it may have been Kipling's parody of the original. As a Kipling parody of someone else's work, it would not, therefore, have been included in any volumes of his own.

Christmas in the Workhouse

It was Christmas in the workhouse
The best day of the year
And the paupers all was 'appy
For their guts was full of beer

The master of the workhouse
Strolled through them dismal 'alls
And he wished them all merry Christmas
And the paupers answered (balls)!

Now the master, he grew angry
And he swore by all the gods
"They'll have no Christmas puddin'
The lousy lot of (cods)!" (the son substituted 'sods')

Up sprang a war-scarred veteran
Who stormed the Kyber Pass, (probably should be 'who had stormed' or 'who'd stormed')
"We don't want your Christmas puddin',
and (you can shove it up your ass)!"