When a ReviewBot RepositoryTool clones, it runs git clone with the

--local flag, which among other things, saves space by using

hardlinks. Since repository.py attempts to clone into /tmp, which

is often a ramdisk, it's considered a separate device. Hardlinks don't

support this, so the tool fails to run with:
fatal: failed to create link <path> Invalid cross-device link
This patch adds --no-hardlinks to the clone which allows us to still

use /tmp, but it doesn't fail on local repositories.

I've tested this by adding a new review request after patching which

correctly clones and runs my own reviewbot plugin.