Exclude 'MESOS_' from environment variable of Dockerfile.

redjack/mesos-master and redjack/mesos-slave does not start.
Collision of environment variables by 'MESOS_VERSION'.
Propose to rename 'MESOS_VERSION' and 'MESOS_PKG_RELEASE'.

```
* LOG

core@master01 ~ $ docker run --rm redjack/mesos-master
Failed to load flag 'version': Failed to load value '0.21.0': Expecting a boolean (e.g., true or false)
Usage: mesos-master [...]

...
```