Description of problem:
A conflict occurs in the dnf transaction when nbdkit* packages are installed on the system.

Version-Release number of selected component (if applicable):
leapp-upgrade-el7toel8-0.17.0-1.el7_9

How reproducible:
Always

Steps to Reproduce:
# yum install nbdkit nbdkit-plugin-python2 nbdkit-plugin-python-common nbdkit-plugin-vddk
# leapp upgrade

Actual results:
 Problem: cannot install the best update candidate for package nbdkit-1.8.0-4.el7.x86_64
  - problem with installed package nbdkit-1.8.0-4.el7.x86_64
  - package nbdkit-1.24.0-4.module+el8.6.0+14480+c0a3aa0f.x86_64 requires nbdkit-server(x86-64) = 1.24.0-4.module+el8.6.0+14480+c0a3aa0f, but none of the providers can be installed
  - package nbdkit-server-1.16.2-4.module+el8.3.0+6922+fd575af8.x86_64 conflicts with nbdkit < 1.12 provided by nbdkit-1.4.2-4.module+el8+2586+bf759444.x86_64
  - package nbdkit-server-1.16.2-4.module+el8.3.0+6922+fd575af8.x86_64 conflicts with nbdkit < 1.12 provided by nbdkit-1.4.2-4.module+el8.0.0.z+3418+a72cf898.x86_64
  - package nbdkit-server-1.16.2-4.module+el8.3.0+6922+fd575af8.x86_64 conflicts with nbdkit < 1.12 provided by nbdkit-1.4.2-5.module+el8.0.0+4084+cceb9f44.x86_64
  - package nbdkit-server-1.16.2-4.module+el8.3.0+6922+fd575af8.x86_64 conflicts with nbdkit < 1.12 provided by nbdkit-1.4.2-4.module+el8.0.0+3075+09be6b65.x86_64
  - package nbdkit-server-1.16.2-4.module+el8.3.0+6922+fd575af8.x86_64 conflicts with nbdkit < 1.12 provided by nbdkit-1.4.2-5.module+el8.1.0+4066+0f1aadab.x86_64
  - cannot install both nbdkit-server-1.24.0-4.module+el8.6.0+14480+c0a3aa0f.x86_64 and nbdkit-server-1.16.2-4.module+el8.3.0+6922+fd575af8.x86_64
  - package nbdkit-python-plugin-1.16.2-4.module+el8.3.0+6922+fd575af8.x86_64 requires nbdkit-server(x86-64) = 1.16.2-4.module+el8.3.0+6922+fd575af8, but none of the providers can be installed
  - cannot install the best candidate for the job
  - nbdkit-1.8.0-4.el7.x86_64 does not belong to a distupgrade repository

Additional info:
- Removing nbdkit* packages workarounds the issue.