341415cdcb
Really fixing 2 things:
1. Panic when any error is detected while walking the btrfs graph dir on
removal due to no error check.
2. Nested subvolumes weren't actually being removed due to passing in
the wrong path
On point 2, for a path detected as a nested subvolume, we were calling
`subvolDelete("/path/to/subvol", "subvol")`, where the last part of the
path was duplicated due to a logic error, and as such actually causing
point #1 since `subvolDelete` joins the two arguemtns, and
`/path/to/subvol/subvol` (the joined version) doesn't exist.
Also adds a test for nested subvol delete.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Upstream-commit: f9befce2d38614de3dfa474bc0f2e1b9937a8ca2
Component: engine