Bug#952849: [live-build] rootfs deletion of file from wrong location

[jnqnfe]

Package: live-build
Version: 1:20191221
Owner: jnq...@gmail.com

the binary_rootfs script incorrectly tries to delete
chroot/chroot/excludes instead of chroot/excludes.

patch to be submitted via salsa shortly (will amend commit with bug
number first)