Doesn't handle multiple, similar, reference to the same file

See original issue here: [https://github.com/rickharrison/broccoli-asset-rev/issues/116](https://github.com/rickharrison/broccoli-asset-rev/issues/116)

Given the input:
```


```

And a fingerprint of `https://mycdn.com/`

The output is:
```


```

(Note the incorrect slash at the start of the second URL.)

This can be avoided by using the exact same URLs everywhere in your source code. It would be nice, however, if the rewrite engine handled this automatically (eg a sort to process the longer replacements first?)