Weldr API used to determine the distro name from the image type, when it
was getting the repositories to use for depsolving and for the actual
depsolving (solver uses the distro name to namespace cache).
This used to be OK, but with the introduction of distro name aliases,
the distro name used to get the distro object may not be the same as the
name returned by the actual distro object. To preserve the current
behavior, the same name used to get the distro object should be used to
also get the repositories for depsolving and to namespace depsolving
cache.
Signed-off-by: Tomáš Hozza <thozza@redhat.com>