Correct the FROM namespace

Was throwing error
```
Step 0 : FROM friism/aspnet:1.0.0-beta1-onbuild
Pulling repository friism/aspnet
2014/12/15 14:07:01 Error: image friism/aspnet not found
```

Now
```
Step 0 : FROM friism/aspnet-docker:1.0.0-beta1-onbuild
Pulling repository friism/aspnet-docker
495c54d0e25f: Download complete
```