Installing the web service init script does not work without rvm

```
# rake init:install
rake aborted!
Errno::ENOENT: No such file or directory - rvm
/home/tmc/srv/tmc-sandbox/web/Rakefile:51:in ``'
/home/tmc/srv/tmc-sandbox/web/Rakefile:51:in `block (2 levels) in <top (required)>'
/var/lib/gems/2.3.0/gems/rake-11.2.2/exe/rake:27:in `<top (required)>'
Tasks: TOP => init:install
(See full trace by running task with --trace)
```
