`ls-remote` errors with the cache file

`dvm ls-remote` shows an unexpected error message before the versions list if the cache file exists.

```bash
$ dvm ls-remote
head: -n: No such file or directory
head: 1: No such file or directory
v0.1.0
# ...
```

And it will fetch the remote versions again and append them to the cache file.

```
v0.1.0
# ...
v2.0.4
v0.1.0
# ...
```