diff gems have the same bin names

```
# gem install bosh_cli_plugin_micro -v "~> 1.5.0.pre" --source http://s3.amazonaws.com/bosh-jenkins-gems/
...
Fetching: bosh_registry-1.5.0.pre.799.gem (100%)
bosh_registry's executable "migrate" conflicts with director
Overwrite the executable? [yN]  y
bosh_registry's executable "migrate" conflicts with director
Overwrite the executable? [yN]  y
```