better handling/docs of missing `rustup` about opensk HOT 2 CLOSED

Perfect and quick - thanks very much!

For anyone else who happens to run into this, just blow your local repo away and re-clone. Otherwise, your local OpenSK will be in a nonfunctional state; running ./setup.sh will fail to properly apply patches, and you'll get a jumble of something like this:

$ ./setup.sh 
[-] Applying patch "01-persistent-storage.patch"... error: patch failed: boards/nordic/nrf52dk_base/src/lib.rs:105
error: boards/nordic/nrf52dk_base/src/lib.rs: patch does not apply
error: patch failed: chips/nrf52/src/nvmc.rs:3
error: chips/nrf52/src/nvmc.rs: patch does not apply
error: patch failed: kernel/src/callback.rs:50
error: kernel/src/callback.rs: patch does not apply

[etc]

If you encounter this, just remove your repo entirely and re-clone it.

(But I expect that very few people will - there was a very small window of time before this fix was applied, and not many are likely to have pulled and didn't already have the right Rust setup)

Thanks again!

from opensk.

Actually, there was a slightly simpler way. The reset.sh script permits to revert uncommitted changes (including in the submodules) to restore the repository to an almost clean cloned state. I'm adding documentation in #31.

from opensk.