Description of problem:
On Satellite 6.4, attempting to change a hosts service level via the hammer cli fails stating that a numeric value is required instead of accepting a string:

[root@galileo ~]# hammer host update --service-level=PREMIUM --id 43
Could not update the host:
  Error: Option '--service-level': Numeric value is required..
  
  See: 'hammer host update --help'.


Version-Release number of selected component (if applicable):
Satellite 6.4

How reproducible:
100%

Steps to Reproduce:
1. Login to a Satellite 6.4 system via the command line
2. Attempt to update a hosts service level via `hammer host update --service-level=PREMIUM --id [MYHOSTID]`
3.


Actual results:

[root@galileo ~]# hammer host update --service-level=PREMIUM --id 43
Could not update the host:
  Error: Option '--service-level': Numeric value is required..
  
  See: 'hammer host update --help'.


Expected results:
It should update the host service level as it previously did in satellite 6.3

Additional info:
Error from commit:

https://github.com/Katello/katello/commit/29f42a35bb9eddcfc8271bc1e3d1dd569579134d#diff-beaa1cde8d4964406e1f688ae9de5befR10

error in app/controllers/katello/api/v2/host_subscriptions_controller.rb

line #10

wrong:
      param :service_level, Integer, :desc => N_("Service level to be used for autoheal.")

correct:
      param :service_level, String, :desc => N_("Service level to be used for autoheal.")


Error:

[DEBUG 2019-01-31T16:42:01 Exception] Using exception handler HammerCLIForeman::ExceptionHandler#handle_usage_exception
[ERROR 2019-01-31T16:42:01 Exception] Error: Option '--service-level': Numeric value is required..

See: 'hammer host update --help'.
Could not update the host:
  Error: Option '--service-level': Numeric value is required..
  
  See: 'hammer host update --help'.
[ERROR 2019-01-31T16:42:01 Exception] 

Clamp::UsageError (Option '--service-level': Numeric value is required..):
    /opt/theforeman/tfm/root/usr/share/gems/gems/clamp-1.1.2/lib/clamp/option/parsing.rb:41:in `rescue in set_options_from_command_line'
    /opt/theforeman/tfm/root/usr/share/gems/gems/clamp-1.1.2/lib/clamp/option/parsing.rb:38:in `set_options_from_command_line'
    /opt/theforeman/tfm/root/usr/share/gems/gems/clamp-1.1.2/lib/clamp/option/parsing.rb:9:in `parse_options'
    /opt/theforeman/tfm/root/usr/share/gems/gems/clamp-1.1.2/lib/clamp/command.rb:48:in `parse'
    /opt/theforeman/tfm/root/usr/share/gems/gems/hammer_cli-0.13.1.1/lib/hammer_cli/abstract.rb:40:in `parse'
    /opt/theforeman/tfm/root/usr/share/gems/gems/clamp-1.1.2/lib/clamp/command.rb:62:in `run'
    /opt/theforeman/tfm/root/usr/share/gems/gems/hammer_cli-0.13.1.1/lib/hammer_cli/abstract.rb:29:in `run'
    /opt/theforeman/tfm/root/usr/share/gems/gems/clamp-1.1.2/lib/clamp/subcommand/execution.rb:11:in `execute'
    /opt/theforeman/tfm/root/usr/share/gems/gems/clamp-1.1.2/lib/clamp/command.rb:63:in `run'
    /opt/theforeman/tfm/root/usr/share/gems/gems/hammer_cli-0.13.1.1/lib/hammer_cli/abstract.rb:29:in `run'
    /opt/theforeman/tfm/root/usr/share/gems/gems/clamp-1.1.2/lib/clamp/subcommand/execution.rb:11:in `execute'
    /opt/theforeman/tfm/root/usr/share/gems/gems/clamp-1.1.2/lib/clamp/command.rb:63:in `run'
    /opt/theforeman/tfm/root/usr/share/gems/gems/hammer_cli-0.13.1.1/lib/hammer_cli/abstract.rb:29:in `run'
    /opt/theforeman/tfm/root/usr/share/gems/gems/clamp-1.1.2/lib/clamp/command.rb:132:in `run'
    /opt/theforeman/tfm/root/usr/share/gems/gems/hammer_cli-0.13.1.1/bin/hammer:143:in `<top (required)>'
    /usr/bin/hammer:23:in `load'
    /usr/bin/hammer:23:in `<main>'

Workaround:

change /opt/theforeman/tfm/root/usr/share/gems/gems/katello-3.7.0.42/app/controllers/katello/api/v2/host_subscriptions_controller.rb

from:
      param :service_level, Integer, :desc => N_("Service level to be used for autoheal.")

to:
      param :service_level, String, :desc => N_("Service level to be used for autoheal.")

FOREMAN_APIPIE_LANGS=en foreman-rake apipie:cache
hammer -dr