largefile: fix up hasattr usage

hgext: add largefiles extension This code has a number of contributors and a complicated history prior to its introduction that can be seen by visiting: https://developers.kilnhg.com/Repo/Kiln/largefiles/largefiles http://hg.gerg.ca/hg-bfiles and looking at the included copyright notices and contributors list.

merge with stable

patchbomb: drop loop in prompt There are no longer any prompts that insist on being answered, so the loop is no longer needed, nor is most of the other logic.