Correctly regex parse Procfile

The following valid Procfile:

```
web: PATH=$HUBOT_PATHS:$PATH && bin/hubot --name $HUBOT_USER --adapter $ADAPTER --alias '/'
```

Would incorrectly be part of the UpStart script as

```
exec PATH=$HUBOT_PATHS  >> /opt/hubot/shared/log/sites/hubot/web-1.log 2>&1
```

Instead of the valid

```
exec PATH=$HUBOT_PATHS:$PATH && bin/hubot --name $HUBOT_USER --adapter $ADAPTER --alias '/' >> /opt/hubot/shared/log/sites/hubot/web-1.log 2>&1
```