Issue

• When tried to use hammer hostgroup update to change a certain value, some other configurations about the host is lost.
• For example:

Have a host group with following puppet settings:

# hammer hostgroup info --name rhel7-abc-client-lab | grep -A1 Puppet
Puppet CA Proxy Id:     2
Puppet Master Proxy Id: 2
ComputeProfile:
Puppetclasses:
    abc::el7all

If updated the Puppetclasses parameter, loosing the information about puppet proxy:

# hammer hostgroup update --name rhel7-abc-client-lab --puppet-classes 'abc::el7all'
Hostgroup updated
# hammer hostgroup info --name rhel7-abc-client-lab | grep -A1 Puppet
Puppet CA Proxy Id:
Puppet Master Proxy Id:
ComputeProfile:
Puppetclasses:
    abc::el7all

And vise versa.

• Updating a single parameter shouldn't affect other parameters. Unless there is any dependences, which should be clearly documented.