Cannot add new entry with if a hostname is a substring of an existing entry's hostname 

I created this bug and here is a patch for it as well as a unit test.  When an entry is added with a hostname that is a substring of an existing entry's hostname, the former is not added because storm thinks it exists already. 

For example: 

```bash
$ storm list
listing entries:

    google-01 -> vagrant@google.com:24

    google-02 -> vagrant@google.com:22


$ storm add goog vagrant@google.com
error    goog is already in your sshconfig. use storm edit command to modify.
```