Remove reference to no longer needed host version

Seemed to fix and allow build creation to proceed.

Original error:
```
rake build:tar
rake aborted!
No such file or directory - /home/jprause/tagging/manageiq/host/miqhost/VERSION
/home/jprause/tagging/manageiq/build/Rakefile:36:in `write'
/home/jprause/tagging/manageiq/build/Rakefile:36:in `block (2 levels) in <top (required)>'
/home/jprause/.rvm/gems/ruby-1.9.3-p551/bin/ruby_executable_hooks:15:in `eval'
/home/jprause/.rvm/gems/ruby-1.9.3-p551/bin/ruby_executable_hooks:15:in `<main>'
Tasks: TOP => build:tar => build:version_files
(See full trace by running task with --trace)
```