In some cases when the host has, for whatever reason, multiple copies of
the same repo listed the build may fail with an error about running out
of space.
So this commit removes duplicate entries after the host's repos have been
loaded. It also adjusts some of the test repos to use different
temporary repo names for the tests.
(cherry picked from commit 98482e444d)
Stop using fake dnf object, use the real thing. This will help catch
problems with dnf returning unexpected types like VectorString.
(cherry picked from commit 27aff75aa3)