parse with hyphen inside the Bracket format cant be recognized 

```
rp = parse.parse("RHEL-{rhel-version}-OSE-{ose-version}", pv)
rb = parse.parse("rhaos-{ose-version}-rhel-{rhel-version}", branch)

rp['rhel-version']  == None
```
but when I change to
```
rp = parse.parse("RHEL-{rhel}-OSE-{ose}", pv)
rb = parse.parse("rhaos-{ose}-rhel-{rhel}", branch)
```

it works