Replace all fmt.Errorf and errors.New in production code with
coreerr.E("Caller.Method", "message", err) from go-log. Replace
os.MkdirAll with coreio.Local.EnsureDir from go-io. Sentinel errors
(consensus/errors.go, wire/varint.go) intentionally kept as errors.New
for errors.Is compatibility.
270 error call sites converted across 38 files. Test files untouched.
crypto/ directory (CGO) untouched.
Co-Authored-By: Virgil <virgil@lethean.io>
71f0a5c1d5