The rbt patch --json output has had some cleanups designed to help

identify failed patches, to avoid failure on warnings, and to add

consistency with other JSON updates.
When a patch fails to apply, failed_patch_num will now be set to the

patch number. This can help with debugging the application of multiple

patches.
The total number of patches is now recorded in total_patches, rather

than n_patches.
review_request has been renamed to review_request_id, and

review_request_url has been added. review_request_id is now

an integer, rather than a string.
If the working directory is clean, we now warn, rather than erroring

out. Previously, the error would cause status to be failed, even if

the patch was successful. Reducing this to a warning avoids this

problem.

Tested applying patches and triggering the various errors. Checked to

make sure I was getting the payloads I expected in each case.
Tested with an unclean working directory. Verified I got a warning, but

it still completed successfully.