Installation source in hostgroup cannot be changed from "synced content" to local medium
In a hostgroup where "synced content" is chosen as installation source it is not possible to change the source a to local medium. Trying to do so does not throw an error but when checking the value afterwards it still says "synced content".
The only currently possible workaround is to change the operating system, save the hostgroup and afterwards editting the hostgroup by changing the operating system back to the original value AND setting the correct medium.
This error only appears in this direction, changing from local medium to "synced content" works without a problem.
Steps to Reproduce:
1. Create a hostgroup
2. Choose "synced content" as installation source
3. Save the hostgroup
4. Edit the hostgroup and change the installation source to local medium
5. Save the hostgroup and check the value
Installation source still is "synced content"
Installation source is previously chosen medium
Before the PR -
On create hostgroups page the inheritance hierachy behavior was different
between katello attribute like content_view/lce/content source etc vs
things like os and arch
For example if you create a child hostgroup and ppointed to a parent
with contnet view, you would see the cv automatically selected as the
default, instead of 'Inherit Content View' as os/arch fields behave.
More over if you had cv, lce, cs, arch filled in the parent hostgroup
and enabled operating system in the child the media section would not
get automatically populated (because the notion of parent_id was
Both the above cases behave appropriately.