hammer host-collection add-host/remove-host always return success
Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1335559
Description of problem:
The `hammer host-collection add-host/remove-host` commands always return success messages, regardless of whether the hosts added/removed are found.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Run the following hammer commands with a valid host collection but invalid host ids
`hammer host-collection add-host --id 1 --host-ids 2354,34`
`hammer host-collection remove-host --id 1 --host-ids 2354,34`
The host(s) has been added
The host(s) has been removed
Could not find hosts with IDs 2354,34. No hosts added.
Could not find hosts with IDs 2354,34. No hosts removed.