fixes #8765 - rpm should require foreman_bootdisk

Fixes broken BATS tests.  The gem requires foreman_bootdisk, the RPM should as well.

Tests are failing because the gem won't load:
```
# hammer -u admin -p changeme repository list --organization-id 1
Warning: An error occured while loading module hammer_cli_katello
Error: No such sub-command 'repository'

See: 'hammer --help'
[root@prometheus yum.repos.d]# 
```
Shouldn't the versions match those specified in .gemspec? 
(I'm actually more concerned about the hammer_cli dependency than the bootdisk plugin)