Since bbolt uses syscalls for memory mapping that aren't available in
JS/WASM builds, we need to make sure we don't reference that code at
all. Otherwise we can't use parts of lnd as a library in projects that
are being compiled down to a WASM binary.
We only want to register the bbolt DB backend ("bdb") when we're not
compiling for a JS/WASM build targets. That's why we want to have that
import in only one file that we can add a build tag to. We remove it in
two other places since only one import is enough anyway.
This commit removes an assertion which is not needed because with etcd
we can safely create keys and values with the same key since they are
stored under different keys in the DB. This saves us one unnecessary Get
on every Put.
The etcd cursor Delete stepped to the next item in the range before
Delete to not invalidate the iteation. This is unnecessary and not
compatible with bbolt, resulting in an extra fetch too.
From bbolt docs:
// Seek positions the cursor at the passed seek key. If the key does not exist,
// the cursor is moved to the next key after seek. Returns the new pair.
