Description of problem:
In a fresh 6.10 or machine migrated from 6.9 to 6.10, once we execute the command "foreman-maintain content migration-stats" we are getting a traceback instead of a nice and welcome warning. Basically, we are not handling the exception.

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


How reproducible:
100%

Steps to Reproduce:
1. Install a fresh 6.10 or upgrade from 6.9 -> 6.10
2. Execute the command "foreman-maintain content  migration-stats"
3.

Actual results:
---
[root@ito-test ~]# foreman-maintain content  migration-stats
Running Retrieve Pulp 2 to Pulp 3 migration statistics
================================================================================
Retrieve Pulp 2 to Pulp 3 migration statistics:                       [FAIL]
Failed executing foreman-rake katello:pulp3_migration_stats, exit status 1:
 'ErbParser' is ignored.
'RubyParser' is ignored.
rake aborted!
Don't know how to build task 'katello:pulp3_migration_stats' (See the list of available tasks with `rake --tasks`)
Did you mean?  katello:import_subscriptions
/opt/rh/rh-ruby27/root/usr/share/gems/gems/rake-13.0.1/exe/rake:27:in `<top (required)>'
(See full trace by running task with --trace)
--------------------------------------------------------------------------------
Scenario [Retrieve Pulp 2 to Pulp 3 migration statistics] failed.

The following steps ended up in failing state:

  [content-migration-stats]

Resolve the failed steps and rerun
the command. In case the failures are false positives,
use --whitelist="content-migration-stats"


[root@ito-test ~]# 
---

Expected results:

Nice information letting the customer know that this command is not necessary anymore, or nothing to be migrated at this moment, once the data is already in pulp3.


Additional info: