Description of problem:

Most of the events here, e.g. in [1], should run only if engine is enabled.

[1] setup/plugins/ovirt-engine-setup/rhevm-setup-plugins/distro-rhel/config.py

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

Probably since 3.5 or so

How reproducible:

Always I think, didn't try

Steps to Reproduce:
1. Install and setup engine+dwh on machine A
2. Install engine+reports on machine B
3. Run engine-setup on machine B, choose to configure only Reports (using existing engine+dwh from machine A)

Actual results:

I think that some plugins will fail while trying to update vdc options.
Even if in scenarios where they do not, they should not run. E.g. if
machine A has engine and on B we ask to configure only dwh+reports, we'll also have A's engine db credentials, thus probably will not fail, but do not want to update vdc options.

Expected results:

A machine setting up things other than the engine should not touch vdc options.

Additional info: