Go 1.10: uuid_test.go:50: Errorf format %d has arg err.Error() of wrong type string

[nim-nim]

179d4d0 does not pass unit tests with Go 1.10

+ GOPATH=/builddir/build/BUILD/gouuid-179d4d0c4d8d407a32af483c2354df1d2c91e6c3/_build:/usr/share/gocode
+ go test -buildmode pie -compiler gc -ldflags '-extldflags '\''-Wl,-z,relro  '\'''
# github.com/nu7hatch/gouuid
./uuid_test.go:50: Errorf format %d has arg err.Error() of wrong type string
./uuid_test.go:98: Errorf format %d has arg err.Error() of wrong type string
FAIL    github.com/nu7hatch/gouuid [build failed]